










                         SENDMAILTM

              INSTALLATION AND OPERATION GUIDE

                        Eric Allman
                    Gregory Neil Shapiro
                       Claus Assmann
                       Sendmail, Inc.

                     Version 8.609.2.29

                 For Sendmail Version 8.12




     SendmailTM  implements  a  general purpose internetwork
mail routing facility under the  UNIX(R)  operating  system.
It is not tied to any one transport protocol -- its function
may be likened to a crossbar switch, relaying messages  from
one  domain  into another.  In the process, it can do a lim-
ited amount of message header editing  to  put  the  message
into  a format that is appropriate for the receiving domain.
All of this is done under the  control  of  a  configuration
file.

     Due  to  the  requirements of flexibility for sendmail,
the configuration file  can  seem  somewhat  unapproachable.
However,  there are only a few basic configurations for most
sites, for which standard configuration files have been sup-
plied.   Most other configurations can be built by adjusting
an existing configuration file incrementally.

     Sendmail is based on RFC  821  (Simple  Mail  Transport
Protocol),  RFC  822 (Internet Mail Headers Format), RFC 974
(MX routing), RFC 1123  (Internet  Host  Requirements),  RFC
1413 (Identification server), RFC 1652 (SMTP 8BITMIME Exten-
sion), RFC 1869 (SMTP Service Extensions),  RFC  1870  (SMTP
SIZE  Extension),  RFC  1891 (SMTP Delivery Status Notifica-
tions), RFC 1892 (Multipart/Report), RFC 1893 (Enhanced Mail
System  Status  Codes),  RFC 1894 (Delivery Status Notifica-
tions), RFC 1985 (SMTP Service Extension for Remote  Message
Queue Starting), RFC 2033 (Local Message Transmission Proto-
col),  RFC  2034  (SMTP  Service  Extension  for   Returning
____________________
   DISCLAIMER: This documentation is under modification.
   Sendmail is a trademark of Sendmail, Inc.




Sendmail Installation and Operation Guide           SMM:08-1







SMM:08-2           Sendmail Installation and Operation Guide


Enhanced  Error  Codes),  RFC 2045 (MIME), RFC 2476 (Message
Submission), RFC 2487 (SMTP  Service  Extension  for  Secure
SMTP over TLS), RFC 2554 (SMTP Service Extension for Authen-
tication), RFC 2821 (Simple  Mail  Transfer  Protocol),  RFC
2822  (Internet  Message  Format), RFC 2852 (Deliver By SMTP
Service Extension), and RFC 2920 (SMTP Service Extension for
Command Pipelining).  However, since sendmail is designed to
work in a wider world, in many cases it can be configured to
exceed these protocols.  These cases are described herein.

     Although  sendmail  is intended to run without the need
for monitoring, it has a number of features that may be used
to  monitor  or  adjust  the operation under unusual circum-
stances.  These features are described.

     Section one  describes  how  to  do  a  basic  sendmail
installation.   Section two explains the day-to-day informa-
tion you should know to maintain your mail system.   If  you
have  a  relatively  normal  site, these two sections should
contain sufficient information for you to  install  sendmail
and  keep it happy.  Section three has information regarding
the command line arguments.   Section  four  describes  some
parameters  that  may  be safely tweaked.  Section five con-
tains the nitty-gritty information about  the  configuration
file.   This  section  is for masochists and people who must
write their own configuration file.  Section  six  describes
configuration  that  can  be  done  at  compile  time.   The
appendixes give a brief but detailed explanation of a number
of features not described in the rest of the paper.


































Sendmail Installation and Operation Guide           SMM:08-7


1.  BASIC INSTALLATION

        There  are  two  basic steps to installing sendmail.
   First, you have to compile and install  the  binary.   If
   sendmail has already been ported to your operating system
   that should be simple.  Second, you must build a run-time
   configuration  file.   This is a file that sendmail reads
   when it starts up that describes  the  mailers  it  knows
   about, how to parse addresses, how to rewrite the message
   header, and the settings of  various  options.   Although
   the configuration file can be quite complex, a configura-
   tion can usually be built using an M4-based configuration
   language.   Assuming  you have the standard sendmail dis-
   tribution, see cf/README for further information.

        The remainder of  this  section  will  describe  the
   installation  of sendmail assuming you can use one of the
   existing configurations and that the  standard  installa-
   tion  parameters are acceptable.  All pathnames and exam-
   ples are given from the root  of  the  sendmail  subtree,
   normally  /usr/src/usr.sbin/sendmail on 4.4BSD-based sys-
   tems.

        Continue with the next section if you  need/want  to
   compile  sendmail yourself.  If you have a running binary
   already on your system, you should probably skip to  sec-
   tion 1.2.

   1.1.  Compiling Sendmail

           All  sendmail source is in the sendmail subdirec-
      tory.  To compile sendmail,  "cd"  into  the  sendmail
      directory and type

          ./Build

      This  will  leave the binary in an appropriately named
      subdirectory, e.g., obj.BSD-OS.2.1.i386.  It works for
      multiple  object  versions  compiled  out  of the same
      directory.

      1.1.1.  Tweaking the Build Invocation

              You can give parameters on the Build  command.
         In  most  cases  these are only used when the obj.*
         directory  is  first  created.   To  restart   from
         scratch, use -c.  These commands include:

         -L libdirs
              A list of directories to search for libraries.

         -I incdirs
              A list of directories to  search  for  include










SMM:08-8           Sendmail Installation and Operation Guide


              files.

         -E envar=value
              Set  an  environment  variable to an indicated
              value before compiling.

         -c   Create a new obj.*  tree before running.

         -f siteconfig
              Read the indicated  site  configuration  file.
              If  this  parameter  is  not  specified, Build
              includes   all   of    the    files    $BUILD-
              TOOLS/Site/site.$oscf.m4      and      $BUILD-
              TOOLS/Site/site.config.m4,  where  $BUILDTOOLS
              is  normally ../devtools and $oscf is the same
              name as used on  the  obj.*   directory.   See
              below for a description of the site configura-
              tion file.

         -S   Skip  auto-configuration.   Build  will  avoid
              auto-detecting  libraries if this is set.  All
              libraries and map definitions must  be  speci-
              fied in the site configuration file.

         Most  other  parameters are passed to the make pro-
         gram; for details see $BUILDTOOLS/README.

      1.1.2.  Creating a Site Configuration File

              (This section is not yet complete.   For  now,
         see  the  file  devtools/README  for details.)  See
         sendmail/README for various compilation flags  that
         can be set.

      1.1.3.  Tweaking the Makefile

              Sendmail  supports  two  different formats for
         the local (on disk) version of  databases,  notably
         the aliases database.  At least one of these should
         be defined if at all possible.

         NDBM      The  ``new  DBM''  format,  available  on
                   nearly  all  systems  around today.  This
                   was the preferred format prior to 4.4BSD.
                   It allows such complex things as multiple
                   databases and closing  a  currently  open
                   database.

         NEWDB     The  Berkeley  DB  package.   If you have
                   this, use it.  It  allows  long  records,
                   multiple  open  databases, real in-memory
                   caching, and so forth.   You  can  define
                   this in conjunction with NDBM; if you do,










Sendmail Installation and Operation Guide           SMM:08-9


                   old alias databases are read, but when  a
                   new  database  is  created  it will be in
                   NEWDB format.  As a nasty  hack,  if  you
                   have NEWDB, NDBM, and NIS defined, and if
                   the alias file  name  includes  the  sub-
                   string  "/yp/", sendmail will create both
                   new and old versions of  the  alias  file
                   during   a  newalias  command.   This  is
                   required because the  Sun  NIS/YP  system
                   reads  the DBM version of the alias file.
                   It's ugly as sin, but it works.

         If neither of these are defined, sendmail reads the
         alias  file  into memory on every invocation.  This
         can be slow and should be avoided.  There are  also
         several methods for remote database access:

         LDAP      Lightweight Directory Access Protocol.

         NIS       Sun's  Network Information Services (for-
                   merly YP).

         NISPLUS   Sun's NIS+ services.

         NETINFO   NeXT's NetInfo service.

         HESIOD    Hesiod service (from Athena).

         Other compilation  flags  are  set  in  conf.h  and
         should be predefined for you unless you are porting
         to a new environment.  For more options  see  send-
         mail/README.

      1.1.4.  Compilation and installation

              After  making  the  local system configuration
         described above, You should be able to compile  and
         install the system.  The script "Build" is the best
         approach on most systems:

             ./Build

         This will use uname(1) to create a custom  Makefile
         for your environment.

              If  you are installing in the standard places,
         you should be able to install using

             ./Build install

         This should install the  binary  in  /usr/sbin  and
         create    links    from   /usr/bin/newaliases   and
         /usr/bin/mailq  to  /usr/sbin/sendmail.   On   most










SMM:08-10          Sendmail Installation and Operation Guide


         systems  it will also format and install man pages.
         Notice: as of version 8.12 sendmail will no  longer
         be  installed  set-user-ID root by default.  If you
         really want to use the old method, you can  specify
         it as target:

             ./Build install-set-user-id


   1.2.  Configuration Files

           Sendmail  cannot  operate without a configuration
      file.  The configuration  defines  the  mail  delivery
      mechanisms  understood  at  this  site,  how to access
      them, how to forward email to remote mail systems, and
      a  number  of  tuning  parameters.  This configuration
      file is detailed in the later portion  of  this  docu-
      ment.

           The  sendmail  configuration  can  be daunting at
      first.  The world is complex, and the mail  configura-
      tion  reflects  that.   The  distribution  includes an
      m4-based configuration package that hides a lot of the
      complexity.  See cf/README for details.

           Our  configuration  files  are processed by m4 to
      facilitate local customization; the  directory  cf  of
      the   sendmail  distribution  directory  contains  the
      source files.  This directory contains several  subdi-
      rectories:

      cf        Both   site-dependent  and  site-independent
                descriptions of hosts.  These can be literal
                host  names  (e.g.,  "ucbvax.mc")  when  the
                hosts are gateways or more general  descrip-
                tions  (such  as  "generic-solaris2.mc" as a
                general  description  of  an  SMTP-connected
                host  running Solaris 2.x.  Files ending .mc
                (``M4   Configuration'')   are   the   input
                descriptions;  the  output  is in the corre-
                sponding .cf file.  The general structure of
                these files is described below.

      domain    Site-dependent    subdomain    descriptions.
                These are tied to the way your  organization
                wants   to   do  addressing.   For  example,
                domain/CS.Berkeley.EDU.m4 is our description
                for  hosts in the CS.Berkeley.EDU subdomain.
                These are referenced  using  the  DOMAIN  m4
                macro in the .mc file.

      feature   Definitions  of  specific features that some
                particular host in  your  site  might  want.










Sendmail Installation and Operation Guide          SMM:08-11


                These  are  referenced  using the FEATURE m4
                macro.  An example  feature  is  use_cw_file
                (which    tells    sendmail   to   read   an
                /etc/mail/local-host-names file  on  startup
                to find the set of local names).

      hack      Local  hacks,  referenced  using the HACK m4
                macro.  Try to avoid these.   The  point  of
                having  them  here  is to make it clear that
                they smell.

      m4        Site-independent m4(1)  include  files  that
                have information common to all configuration
                files.   This  can  be  thought  of   as   a
                "#include" directory.

      mailer    Definitions of mailers, referenced using the
                MAILER m4 macro.  The mailer types that  are
                known  in  this distribution are fax, local,
                smtp, uucp, and  usenet.   For  example,  to
                include  support for the UUCP-based mailers,
                use "MAILER(uucp)".

      ostype    Definitions  describing  various   operating
                system environments (such as the location of
                support files).  These are referenced  using
                the OSTYPE m4 macro.

      sh        Shell  files  used  by the m4 build process.
                You shouldn't have to mess with these.

      siteconfig
                Local UUCP connectivity  information.   This
                directory  has  been supplanted by the mail-
                ertable  feature;  any  new   configurations
                should  use  that  feature  to  do UUCP (and
                other) routing.  The use of  this  directory
                is deprecated.

           If you are in a new domain (e.g., a company), you
      will probably want to create a cf/domain file for your
      domain.   This consists primarily of relay definitions
      and features you want enabled site-wide: for  example,
      Berkeley's domain definition defines relays for BitNET
      and UUCP.  These are specific to Berkeley, and  should
      be   fully-qualified   internet-style   domain  names.
      Please check to make certain they are  reasonable  for
      your domain.

           Subdomains  at  Berkeley  are also represented in
      the cf/domain  directory.   For  example,  the  domain
      CS.Berkeley.EDU  is  the  Computer  Science subdomain,
      EECS.Berkeley.EDU is the  Electrical  Engineering  and










SMM:08-12          Sendmail Installation and Operation Guide


      Computer  Sciences  subdomain, and S2K.Berkeley.EDU is
      the Sequoia 2000 subdomain.  You will probably have to
      add  an  entry to this directory to be appropriate for
      your domain.

           You will have to use or create .mc files  in  the
      cf/cf  subdirectory  for your hosts.  This is detailed
      in the cf/README file.

   1.3.  Details of Installation Files

           This subsection describes the files that comprise
      the sendmail installation.

      1.3.1.  /usr/sbin/sendmail

              The   binary   for   sendmail  is  located  in
         /usr/sbin[1].  It should be set-group-ID  smmsp  as
         described  in sendmail/SECURITY.  For security rea-
         sons, /, /usr, and /usr/sbin  should  be  owned  by
         root, mode 0755[2].

      1.3.2.  /etc/mail/sendmail.cf

              This  is the main configuration file for send-
         mail[3].  This is one of the two  non-library  file
         names  compiled  into  sendmail[4],  the  other  is
         /etc/mail/submit.cf.

              The configuration  file  is  normally  created
         using  the  distribution files described above.  If
         you   have   a    particularly    unusual    system
____________________
   [1]This is usually /usr/sbin on 4.4BSD and newer systems;
many  systems install it in /usr/lib.  I understand it is in
/usr/ucblib on System V Release 4.
   [2]Some  vendors  ship  them owned by bin; this creates a
security hole that is  not  actually  related  to  sendmail.
Other  important  directories  that  should have restrictive
ownerships  and  permissions  are  /bin,   /usr/bin,   /etc,
/etc/mail, /usr/etc, /lib, and /usr/lib.
   [3]Actually, the pathname varies depending on the operat-
ing system; /etc/mail is the preferred directory.  Some old-
er systems install it in /usr/lib/sendmail.cf, and I've also
seen  it in /usr/ucblib.  If you want to move this file, add
-D_PATH_SENDMAILCF=\"/file/name\" to the flags passed to the
C compiler.  Moving this file is not recommended: other pro-
grams and scripts know of this location.
   [4]The system libraries can  reference  other  files;  in
particular,  system  library subroutines that sendmail calls
probably reference /etc/passwd and /etc/resolv.conf.












Sendmail Installation and Operation Guide          SMM:08-13


         configuration you may need to create a special ver-
         sion.  The format of this file is detailed in later
         sections of this document.

      1.3.3.  /etc/mail/submit.cf

              This  is  the  configuration file for sendmail
         when it is used for  initial  mail  submission,  in
         which case it is also called ``Mail Submission Pro-
         gram'' (MSP) in contrast to ``Mail Transfer Agent''
         (MTA).   Starting  with version 8.12, sendmail uses
         one of two different configuration files  based  on
         its  operation  mode  (or  the new -A option).  For
         initial  mail  submission,  i.e.,  if  one  of  the
         options  -bm  (default),  -bs,  or -t is specified,
         submit.cf is used (if available), for other  opera-
         tions sendmail.cf is used.  Details can be found in
         sendmail/SECURITY.  submit.cf is shipped with send-
         mail  (in  cf/cf/) and is installed by default.  If
         changes to the configuration need to be made, start
         with  cf/cf/submit.mc and follow the instruction in
         cf/README.

      1.3.4.  /usr/bin/newaliases

              The newaliases command should just be  a  link
         to sendmail:

             rm -f /usr/bin/newaliases
             ln -s /usr/sbin/sendmail /usr/bin/newaliases

         This  can  be installed in whatever search path you
         prefer for your system.

      1.3.5.  /usr/bin/hoststat

              The hoststat command should just be a link  to
         sendmail, in a fashion similar to newaliases.  This
         command lists the status of the last mail  transac-
         tion  with all remote hosts.  The -v flag will pre-
         vent the status display from being  truncated.   It
         functions  only when the HostStatusDirectory option
         is set.

      1.3.6.  /usr/bin/purgestat

              This command is also a link to  sendmail.   It
         flushes  expired  (Timeout.hoststatus)  information
         that is stored in the HostStatusDirectory tree.














SMM:08-14          Sendmail Installation and Operation Guide


      1.3.7.  /var/spool/mqueue

              The directory /var/spool/mqueue should be cre-
         ated to hold the mail queue.  This directory should
         be mode 0700 and owned by root.

              The actual path of this directory  is  defined
         by  the  QueueDirectory  option  of the sendmail.cf
         file.  To use multiple queues, supply a value  end-
         ing     with    an    asterisk.     For    example,
         /var/spool/mqueue/qd* will use all of the  directo-
         ries  or  symbolic  links  to directories beginning
         with `qd' in /var/spool/mqueue  as  queue  directo-
         ries.   Do not change the queue directory structure
         while sendmail is running.

              If these directories  have  subdirectories  or
         symbolic links to directories named `qf', `df', and
         `xf', then these will be  used  for  the  different
         queue  file  types.   That  is,  the data files are
         stored in the  `df'  subdirectory,  the  transcript
         files  are stored in the `xf' subdirectory, and all
         others are stored in the `qf' subdirectory.

              If shared memory support is compiled in, send-
         mail  stores  the  available  diskspace in a shared
         memory segment to make the values readily available
         to  all children without incurring system overhead.
         In this case, only the  daemon  updates  the  data;
         i.e., the sendmail daemon creates the shared memory
         segment and deletes it if it is terminated.  To use
         this, sendmail must have been compiled with support
         for shared memory (-DSM_CONF_SHM)  and  the  option
         SharedMemoryKey  must  be  set.  Notice: do not use
         the same key for sendmail invocations with  differ-
         ent queue directories or different queue group dec-
         larations.  Access to shared  memory  is  not  con-
         trolled  by  locks, i.e., there is a race condition
         when data in the shared memory  is  updated.   How-
         ever,  since operation of sendmail does not rely on
         the data in the shared memory, this does not  nega-
         tively influence the behavior.

      1.3.8.  /var/spool/clientmqueue

              The  directory  /var/spool/clientmqueue should
         be created to hold the mail queue.  This  directory
         should  be mode 0770 and owned by user smmsp, group
         smmsp.

              The actual path of this directory  is  defined
         by the QueueDirectory option of the submit.cf file.











Sendmail Installation and Operation Guide          SMM:08-15


      1.3.9.  /var/spool/mqueue/.hoststat

              This is a typical value for the  HostStatusDi-
         rectory  option,  containing one file per host that
         this sendmail has chatted  with  recently.   It  is
         normally a subdirectory of mqueue.

      1.3.10.  /etc/mail/aliases*

              The     system    aliases    are    held    in
         "/etc/mail/aliases".  A sample is given  in  "send-
         mail/aliases"  which  includes  some  aliases which
         must be defined:

             cp sendmail/aliases /etc/mail/aliases
             edit /etc/mail/aliases

         You should extend this file with any  aliases  that
         are apropos to your system.

              Normally  sendmail looks at a database version
         of     the     files,     stored     either      in
         "/etc/mail/aliases.dir" and "/etc/mail/aliases.pag"
         or "/etc/mail/aliases.db" depending on which  data-
         base  package  you  are  using.  The actual path of
         this file is defined in the AliasFile option of the
         sendmail.cf file.

              The  permissions  of  the  alias  file and the
         database versions should be 0640 to  prevent  local
         denial  of  service attacks as explained in the top
         level README in the sendmail distribution.  If  the
         permissions  0640  are  used,  be  sure  that  only
         trusted users belong to the group assigned to those
         files.   Otherwise,  files should not even be group
         readable.

      1.3.11.  /etc/rc or /etc/init.d/sendmail

              It will be necessary to start up the  sendmail
         daemon  when your system reboots.  This daemon per-
         forms two functions: it listens on the SMTP  socket
         for connections (to receive mail from a remote sys-
         tem) and it processes  the  queue  periodically  to
         insure that mail gets delivered when hosts come up.

              If  necessary,  add  the  following  lines  to
         "/etc/rc"  (or  "/etc/rc.local"  as appropriate) in
         the area where it is starting up the daemons  on  a
         BSD-base  system,  or on a System-V-based system in
         one    of    the    startup    files,     typically
         "/etc/init.d/sendmail":











SMM:08-16          Sendmail Installation and Operation Guide


             if [ -f /usr/sbin/sendmail -a -f /etc/mail/sendmail.cf ]; then
                  (cd /var/spool/mqueue; rm -f xf*)
                  /usr/sbin/sendmail -bd -q30m &
                  echo -n ' sendmail' >/dev/console
             fi

         The  "cd"  and  "rm" commands insure that all tran-
         script files have been  removed;  extraneous  tran-
         script  files may be left around if the system goes
         down in the middle of processing  a  message.   The
         line  that actually invokes sendmail has two flags:
         "-bd" causes it to listen on  the  SMTP  port,  and
         "-q30m" causes it to run the queue every half hour.

              Some people use a more complex startup script,
         removing  zero  length  qf  files  and df files for
         which there is no qf file.  For example, see Figure
         1  for  an  example  of a complex script which does
         this clean up.

      1.3.12.  /etc/mail/helpfile

              This is the help file used by  the  SMTP  HELP
         command.   It should be copied from "sendmail/help-
         file":

             cp sendmail/helpfile /etc/mail/helpfile

         The actual path of this  file  is  defined  in  the
         HelpFile option of the sendmail.cf file.

      1.3.13.  /etc/mail/statistics

              If  you  wish to collect statistics about your
         mail  traffic,   you   should   create   the   file
         "/etc/mail/statistics":

             cp /dev/null /etc/mail/statistics
             chmod 0600 /etc/mail/statistics

         This  file  does  not grow.  It is printed with the
         program "mailstats/mailstats.c."  The  actual  path
         of  this  file  is  defined  in the S option of the
         sendmail.cf file.

      1.3.14.  /usr/bin/mailq

              If sendmail is invoked  as  "mailq,"  it  will
         simulate  the  -bp  flag (i.e., sendmail will print
         the contents of the mail queue; see  below).   This
         should be a link to /usr/sbin/sendmail.












Sendmail Installation and Operation Guide          SMM:08-17



____________________________________________________________

#!/bin/sh
# remove zero length qf files
for qffile in qf*
do
     if [ -r $qffile ]
     then
          if [ ! -s $qffile ]
          then
               echo -n " <zero: $qffile>" > /dev/console
               rm -f $qffile
          fi
     fi
done
# rename tf files to be qf if the qf does not exist
for tffile in tf*
do
     qffile=`echo $tffile | sed 's/t/q/'`
     if [ -r $tffile -a ! -f $qffile ]
     then
          echo -n " <recovering: $tffile>" > /dev/console
          mv $tffile $qffile
     else
          if [ -f $tffile ]
          then
               echo -n " <extra: $tffile>" > /dev/console
               rm -f $tffile
          fi
     fi
done
# remove df files with no corresponding qf files
for dffile in df*
do
     qffile=`echo $dffile | sed 's/d/q/'`
     if [ -r $dffile -a ! -f $qffile ]
     then
          echo -n " <incomplete: $dffile>" > /dev/console
          mv $dffile `echo $dffile | sed 's/d/D/'`
     fi
done
# announce files that have been saved during disaster recovery
for xffile in [A-Z]f*
do
     if [ -f $xffile ]
     then
          echo -n " <panic: $xffile>" > /dev/console
     fi
done

            Figure 1 -- A complex startup script
____________________________________________________________










SMM:08-18          Sendmail Installation and Operation Guide


      1.3.15.  sendmail.pid

              sendmail  stores  its  current pid in the file
         specifed  by  the  PidFile   option   (default   is
         _PATH_SENDMAILPID).    sendmail  uses  TempFileMode
         (which defaults to 0600) as the permissions of that
         file  to prevent local denial of service attacks as
         explained in the top level README in  the  sendmail
         distribution.   If the file already exists, then it
         might  be  necessary  to  change  the   permissions
         accordingly, e.g.,

             chmod 0600 /var/run/sendmail.pid


      1.3.16.  Map Files

              To  prevent local denial of service attacks as
         explained in the top level README in  the  sendmail
         distribution,  the permissions of map files created
         by makemap should be 0640.  The use of 0640 implies
         that   only  trusted  users  belong  to  the  group
         assigned to those files.  If  those  files  already
         exist,  then  it  might  be necessary to change the
         permissions accordingly, e.g.,

             cd /etc/mail
             chmod 0640 *.db *.pag *.dir


2.  NORMAL OPERATIONS

   2.1.  The System Log

           The system log is  supported  by  the  syslogd(8)
      program.   All messages from sendmail are logged under
      the LOG_MAIL facility[5].

      2.1.1.  Format

              Each  line  in  the  system  log consists of a
         timestamp, the name of the machine  that  generated
         it  (for  logging  from  several  machines over the
         local area network), the word  "sendmail:",  and  a
         message[6].   Most  messages  are  a  sequence   of
         name=value pairs.
____________________
   [5]Except on Ultrix, which does not support facilities in
the syslog.
   [6]This  format  may  vary  slightly  if  your vendor has
changed the syntax.












Sendmail Installation and Operation Guide          SMM:08-19


              The  two  most  common lines are logged when a
         message is processed.  The first logs  the  receipt
         of  a  message;  there will be exactly one of these
         per message.  Some fields may be omitted if they do
         not contain interesting information.  Fields are:

         from      The envelope sender address.

         size      The size of the message in bytes.

         class     The  class  (i.e., numeric precedence) of
                   the message.

         pri       The initial message  priority  (used  for
                   queue sorting).

         nrcpts    The  number  of  envelope  recipients for
                   this message (after aliasing and forward-
                   ing).

         msgid     The  message  id of the message (from the
                   header).

         proto     The protocol used to receive this message
                   (e.g., ESMTP or UUCP)

         daemon    The  daemon  name  from the DaemonPortOp-
                   tions setting.

         relay     The machine from which it was received.

         There is also one line logged per delivery  attempt
         (so there can be several per message if delivery is
         deferred or there are multiple recipients).  Fields
         are:

         to        A  comma-separated list of the recipients
                   to this mailer.

         ctladdr   The ``controlling user'',  that  is,  the
                   name of the user whose credentials we use
                   for delivery.

         delay     The total delay  between  the  time  this
                   message  was  received  and  the  current
                   delivery attempt.

         xdelay    The amount of time needed in this  deliv-
                   ery  attempt  (normally indicative of the
                   speed of the connection).

         mailer    The name of the mailer used to deliver to
                   this recipient.










SMM:08-20          Sendmail Installation and Operation Guide


         relay     The   name  of  the  host  that  actually
                   accepted (or rejected) this recipient.

         dsn       The enhanced error  code  (RFC  2034)  if
                   available.

         stat      The delivery status.

         Not  all  fields  are  present in all messages; for
         example, the relay is usually not listed for  local
         deliveries.

      2.1.2.  Levels

              If   you  have  syslogd(8)  or  an  equivalent
         installed, you will be able to do  logging.   There
         is  a  large  amount  of  information  that  can be
         logged.  The log is arranged  as  a  succession  of
         levels.  At the lowest level only extremely strange
         situations are logged.  At the highest level,  even
         the  most  mundane  and  uninteresting  events  are
         recorded for posterity.  As a convention, log  lev-
         els  under  ten  are considered generally "useful;"
         log levels above 64 are reserved for debugging pur-
         poses.   Levels from 11-64 are reserved for verbose
         information that some sites might want.

              A complete description of the  log  levels  is
         given in section 4.7.

   2.2.  Dumping State

           You  can  ask  sendmail to log a dump of the open
      files and the connection cache by sending it a SIGUSR1
      signal.  The results are logged at LOG_DEBUG priority.

   2.3.  The Mail Queues

           Mail messages may either be delivered immediately
      or  be  held  for  later  delivery.  Held messages are
      placed into a holding directory called a mail queue.

           A mail message may be queued for these reasons:

       + If a mail message is temporarily undeliverable,  it
         is  queued and delivery is attempted later.  If the
         message is addressed to multiple recipients, it  is
         queued  only  for those recipients to whom delivery
         is not immediately possible.
       + If the SuperSafe option is set to  true,  all  mail
         messages are queued while delivery is attempted.
       + If  the DeliveryMode option is set to queue-only or
         defer,  all  mail  is  queued,  and  no   immediate










Sendmail Installation and Operation Guide          SMM:08-21


         delivery is attempted.
       + If  the  load average becomes higher than the value
         of the  QueueLA  option  and  the  QueueFactor  (q)
         option  divided  by  the  difference in the current
         load average and the QueueLA  option  plus  one  is
         less than the priority of the message, messages are
         queued rather than immediately delivered.
       + One or more addresses are marked as  expensive  and
         delivery  is  postponed until the next queue run or
         one or more address are marked as held  via  mailer
         which uses the hold mailer flag.

      2.3.1.  Queue Groups and Queue Directories

              There  are one or more mail queues.  Each mail
         queue belongs to a queue group.  There is always  a
         default  queue  group  that  is  called  ``mqueue''
         (which is where messages go by default unless  oth-
         erwise  specified).   The  directory or directories
         which comprise the default queue group  are  speci-
         fied  by the QueueDirectory option.  There are zero
         or more  additional  named  queue  groups  declared
         using the Q command in the configuration file.

              By  default, a queued message is placed in the
         queue group associated with the first recipient  in
         the  recipient list.  A recipient address is mapped
         to a queue group as follows.  First, if there is  a
         ruleset  called ``queuegroup'', and if this ruleset
         maps the address to a queue group name,  then  that
         queue  group  is chosen.  That is, the argument for
         the ruleset is the recipient address and the result
         should be $# followed by the name of a queue group.
         Otherwise,  if  the  mailer  associated  with   the
         address  specifies  a  queue group, then that queue
         group is  chosen.   Otherwise,  the  default  queue
         group is chosen.

              A  message  with  multiple  recipients will be
         split if different queue groups are chosen  by  the
         mapping of recipients to queue groups.

              When a message is placed in a queue group, and
         the queue group has more than one queue, a queue is
         selected randomly.

              If  a  message  with  multiple  recipients  is
         placed into a queue group with the 'r' option (max-
         imum  number  of  recipients  per message) set to a
         positive value N, and if  there  are  more  than  N
         recipients in the message, then the message will be
         split into multiple messages, each of which have at
         most N recipients.










SMM:08-22          Sendmail Installation and Operation Guide


              Notice:  if multiple queue groups are used, do
         not move queue files around, e.g., into a different
         queue  directory.   This may have weird effects and
         can cause mail not to be  delivered.   Queue  files
         and  directories  should  be  treated as opaque and
         should not be manipulated directly.

      2.3.2.  Queue Runs

              sendmail has two different ways to process the
         queue(s).   The first one is to start queue runners
         after certain intervals (``normal'' queue runners),
         the  second  one  is to keep queue runner processes
         around  (``persistent''  queue  runners).   How  to
         select  either  of  these types is discussed in the
         appendix ``COMMAND LINE FLAGS''.  Persistent  queue
         runners  have  the  advantage that no new processes
         need to be spawned at certain intervals; they  just
         sleep  for  a  specified time after they finished a
         queue run.  Another advantage of  persistent  queue
         runners  is  that  only  one process belonging to a
         workgroup (a workgroup is a set  of  queue  groups)
         collects the data for a queue run and then multiple
         queue runner may go ahead using  that  data.   This
         can  significantly reduce the disk I/O necessary to
         read the queue files compared to starting  multiple
         queue runners directly.  Their disadvantage is that
         a new queue run is only  started  after  all  queue
         runners  belonging to a group finished their tasks.
         In case one of the queue runners tries delivery  to
         a  slow  recipient  site at the end of a queue run,
         the next queue run may  be  substantially  delayed.
         In  general  this should be smoothed out due to the
         distribution of those slow jobs, however, for sites
         with  small  number  of  queue  entries  this might
         introduce noticable delays.  In general, persistent
         queue  runners  are  only useful for sites with big
         queues.

      2.3.3.  Manual Intervention

              Under normal conditions the mail queue will be
         processed  transparently.   However,  you  may find
         that manual intervention  is  sometimes  necessary.
         For  example,  if a major host is down for a period
         of time the queue  may  become  clogged.   Although
         sendmail  ought to recover gracefully when the host
         comes up, you may find performance unacceptably bad
         in  the  meantime.   In that case you want to check
         the content of  the  queue  and  manipulate  it  as
         explained in the next two sections.












Sendmail Installation and Operation Guide          SMM:08-23


      2.3.4.  Printing the queue

              The  contents  of  the queue(s) can be printed
         using the mailq command (or by specifying  the  -bp
         flag to sendmail):

             mailq

         This  will produce a listing of the queue id's, the
         size of the message, the date the  message  entered
         the  queue,  and  the  sender  and  recipients.  If
         shared memory support is compiled in, the flag  -bP
         can  be  used to print the number of entries in the
         queue(s), provided  a  process  updates  the  data.
         However,  as explained earlier, the output might be
         slightly wrong, since access to the  shared  memory
         is  not  locked.   For example, ``unknown number of
         entries'' might be shown.   The  internal  counters
         are  updated  after  each  queue run to the correct
         value again.

      2.3.5.  Forcing the queue

              Sendmail should run the queue automatically at
         intervals.   When using multiple queues, a separate
         process will by default be created to run  each  of
         the  queues  unless the queue run is initiated by a
         user with the verbose flag.  The  algorithm  is  to
         read  and  sort  the  queue, and then to attempt to
         process all jobs in order.  When it attempts to run
         the job, sendmail first checks to see if the job is
         locked.  If so, it ignores the job.

              There is no attempt to insure  that  only  one
         queue  processor exists at any time, since there is
         no guarantee that a  job  cannot  take  forever  to
         process  (however, sendmail does include heuristics
         to try to abort jobs that are taking absurd amounts
         of time; technically, this violates RFC 821, but is
         blessed by RFC 1123).  Due  to  the  locking  algo-
         rithm,  it  is impossible for one job to freeze the
         entire queue.  However, an uncooperative  recipient
         host  or a program recipient that never returns can
         accumulate many processes in your system.  Unfortu-
         nately, there is no completely general way to solve
         this.

              In some cases, you may find that a major  host
         going  down  for a couple of days may create a pro-
         hibitively large queue.  This will result in  send-
         mail  spending an inordinate amount of time sorting
         the queue.  This situation can be fixed  by  moving
         the  queue  to a temporary place and creating a new










SMM:08-24          Sendmail Installation and Operation Guide


         queue.  The old queue can be  run  later  when  the
         offending host returns to service.

              To  do  this,  it  is  acceptable  to move the
         entire queue directory:

             cd /var/spool
             mv mqueue omqueue; mkdir mqueue; chmod 0700 mqueue

         You should then kill the existing daemon (since  it
         will  still  be  processing in the old queue direc-
         tory) and create a new daemon.

              To run the old mail queue, issue the following
         command:

             /usr/sbin/sendmail -C /etc/mail/queue.cf -q

         The  -C  flag  specifies an alternate configuration
         file queue.cf which should refer to the moved queue
         directory

             O QueueDirectory=/var/spool/omqueue

         and  the  -q flag says to just run every job in the
         queue.  You can also specify the moved queue direc-
         tory on the command line

             /usr/sbin/sendmail -oQ/var/spool/omqueue -q

         but this requires that you do not have queue groups
         in the configuration file, because  those  are  not
         subdirectories  of  the  moved  directory.  See the
         section  about  "Queue   Group   Declaration"   for
         details;  you most likely need a different configu-
         ration file to correctly deal  with  this  problem.
         However,  a  proper  configuration  of queue groups
         should avoid filling up queue directories,  so  you
         shouldn't  run  into  this  problem.  If you have a
         tendency toward voyeurism, you can use the -v  flag
         to watch what is going on.

              When  the  queue  is  finally emptied, you can
         remove the directory:

             rmdir /var/spool/omqueue


   2.4.  Disk Based Connection Information

           Sendmail stores a  large  amount  of  information
      about  each  remote system it has connected to in mem-
      ory.  It  is  possible  to  preserve  some   of   this










Sendmail Installation and Operation Guide          SMM:08-25


      information  on disk as well, by using the HostStatus-
      Directory option, so that it  may  be  shared  between
      several  invocations of sendmail.  This allows mail to
      be queued immediately or skipped during a queue run if
      there  has  been  a  recent failure in connecting to a
      remote machine.

           Additionally  enabling  SingleThreadDelivery  has
      the  added effect of single-threading mail delivery to
      a destination.  This  can  be  quite  helpful  if  the
      remote  machine is running an SMTP server that is eas-
      ily overloaded or cannot accept  more  than  a  single
      connection  at  a time, but can cause some messages to
      be punted to a future queue run.  It also  applies  to
      all  hosts,  so  setting  this  because  you  have one
      machine on site that runs some software that is easily
      overrun  can  cause  mail  to other hosts to be slowed
      down.  If this option is set, you probably want to set
      the  MinQueueAge  option  as  well  and  run the queue
      fairly frequently; this  way  jobs  that  are  skipped
      because  another  sendmail is talking to the same host
      will be tried again quickly rather than being  delayed
      for a long time.

           The  disk  based  host information is stored in a
      subdirectory of the  mqueue  directory  called  .host-
      stat[7].   Removing this directory and its subdirecto-
      ries has an effect similar to  the  purgestat  command
      and  is  completely  safe.   However,  purgestat  only
      removes expired (Timeout.hoststatus) data.  The infor-
      mation  in  these  directories can be perused with the
      hoststat command, which will indicate the  host  name,
      the  last  access,  and the status of that access.  An
      asterisk in the left  most  column  indicates  that  a
      sendmail  process  currently  has  the host locked for
      mail delivery.

           The disk based connection information is  treated
      the  same  way  as memory based connection information
      for the purpose of timeouts.  By default,  information
      about host failures is valid for 30 minutes.  This can
      be adjusted with the Timeout.hoststatus option.

           The connection information stored on disk may  be
      expired  at  any time with the purgestat command or by
      invoking sendmail with the -bH switch.  The connection
      information may be viewed with the hoststat command or
____________________
   [7]This is the usual value of the HostStatusDirectory op-
tion; it can, of  course,  go  anywhere  you  like  in  your
filesystem.












SMM:08-26          Sendmail Installation and Operation Guide


      by invoking sendmail with the -bh switch.

   2.5.  The Service Switch

           The implementation  of  certain  system  services
      such as host and user name lookup is controlled by the
      service switch.  If the host operating system supports
      such  a  switch, and sendmail knows about it, sendmail
      will use the native version.  Ultrix, Solaris, and DEC
      OSF/1 are examples of such systems[8].

           If  the underlying operating system does not sup-
      port a service switch (e.g., SunOS  4.X,  HP-UX,  BSD)
      then sendmail will provide a stub implementation.  The
      ServiceSwitchFile option points to the name of a  file
      that  has  the service definitions.  Each line has the
      name of a service and the possible implementations  of
      that service.  For example, the file:

          hosts     dns files nis
          aliases   files nis

      will ask sendmail to look for hosts in the Domain Name
      System first.  If  the  requested  host  name  is  not
      found,  it  tries  local  files,  and if that fails it
      tries NIS.  Similarly, when  looking  for  aliases  it
      will try the local files first followed by NIS.

           Notice: since sendmail must access MX records for
      correct operation, it will use DNS if it is configured
      in the ServiceSwitchFile file.  Hence an entry like

          hosts     files dns

      will not avoid DNS lookups even if a host can be found
      in /etc/hosts.

           Service switches are not  completely  integrated.
      For  example,  despite  the  fact  that the host entry
      listed in the above example specifies to look in  NIS,
      on  SunOS  this won't happen because the system imple-
      mentation of gethostbyname(3) doesn't understand this.

   2.6.  The Alias Database

           After  recipient addresses are read from the SMTP
      connection or command line they are parsed by  ruleset
____________________
   [8]HP-UX  10  has  service  switch support, but since the
APIs are apparently not available in the libraries  sendmail
does not use the native service switch in this release.












Sendmail Installation and Operation Guide          SMM:08-27


      0,  which  must  resolve  to a {mailer, host, address}
      triple.  If the flags selected by the  mailer  include
      the A (aliasable) flag, the address part of the triple
      is looked up as the key (i.e.,  the  left  hand  side)
      into  the  alias  database.   If there is a match, the
      address  is  deleted  from  the  send  queue  and  all
      addresses  on  the  right  hand  side of the alias are
      added in place of the alias that was found.  This is a
      recursive  operation,  so  aliases  found in the right
      hand side of the alias are similarly expanded.

           The alias database exists in two forms.  One is a
      text  form,  maintained in the file /etc/mail/aliases.
      The aliases are of the form

          name: name1, name2, ...

      Only local names may be aliased; e.g.,

          eric@prep.ai.MIT.EDU: eric@CS.Berkeley.EDU

      will  not  have  the   desired   effect   (except   on
      prep.ai.MIT.EDU,  and they probably don't want me)[9].
      Aliases may be continued by starting any  continuation
      lines  with a space or a tab or by putting a backslash
      directly before the newline.  Blank  lines  and  lines
      beginning with a sharp sign ("#") are comments.

           The  second  form is processed by the ndbm(3)[10]
      or the Berkeley DB library.  This form is in the  file
      /etc/mail/aliases.db     (if     using    NEWDB)    or
      /etc/mail/aliases.dir  and  /etc/mail/aliases.pag  (if
      using  NDBM).  This is the form that sendmail actually
      uses to resolve aliases.  This technique  is  used  to
      improve performance.

           The  control  of  search order is actually set by
      the service switch.  Essentially, the entry

          O AliasFile=switch:aliases

      is always added as the first alias  entry;  also,  the
      first  alias  file name without a class (e.g., without
      "nis:" on the front) will be used as the name  of  the
      file for a ``files'' entry in the aliases switch.  For
      example, if the configuration file contains
____________________
   [9]Actually,  any mailer that has the `A' mailer flag set
will permit aliasing; this is normally limited to the  local
mailer.
   [10]The gdbm package does not work.












SMM:08-28          Sendmail Installation and Operation Guide


          O AliasFile=/etc/mail/aliases

      and the service switch contains

          aliases   nis files nisplus

      then aliases will first be searched in the  NIS  data-
      base,  then  in  /etc/mail/aliases,  then  in the NIS+
      database.

           You can also  use  NIS-based  alias  files.   For
      example, the specification:

          O AliasFile=/etc/mail/aliases
          O AliasFile=nis:mail.aliases@my.nis.domain

      will  first search the /etc/mail/aliases file and then
      the  map  named  "mail.aliases"  in   "my.nis.domain".
      Warning:  if you build your own NIS-based alias files,
      be sure to provide the -l flag to  makedbm(8)  to  map
      upper  case  letters in the keys to lower case; other-
      wise, aliases with upper case letters in  their  names
      won't match incoming addresses.

           Additional  flags  can  be  added after the colon
      exactly like a K line -- for example:

          O AliasFile=nis:-N mail.aliases@my.nis.domain

      will search the appropriate NIS map and always include
      null bytes in the key.  Also:

          O AliasFile=nis:-f mail.aliases@my.nis.domain

      will  prevent  sendmail from downcasing the key before
      the alias lookup.

      2.6.1.  Rebuilding the alias database

              The hash or dbm version of the database may be
         rebuilt explicitly by executing the command

             newaliases

         This is equivalent to giving sendmail the -bi flag:

             /usr/sbin/sendmail -bi


              If you have multiple aliases databases  speci-
         fied,  the -bi flag rebuilds all the database types
         it understands (for example, it  can  rebuild  NDBM
         databases but not NIS databases).










Sendmail Installation and Operation Guide          SMM:08-29


      2.6.2.  Potential problems

              There  are a number of problems that can occur
         with the alias database.  They all  result  from  a
         sendmail process accessing the DBM version while it
         is only partially built.  This can happen under two
         circumstances:  One  process  accesses the database
         while another process  is  rebuilding  it,  or  the
         process  rebuilding the database dies (due to being
         killed or a system  crash)  before  completing  the
         rebuild.

              Sendmail   has  three  techniques  to  try  to
         relieve these problems.  First, it  ignores  inter-
         rupts  while  rebuilding  the database; this avoids
         the problem of someone aborting the process leaving
         a partially rebuilt database.  Second, it locks the
         database source file during the rebuild -- but that
         may not work over NFS or if the file is unwritable.
         Third, at the end of the rebuild it adds  an  alias
         of the form

             @: @

         (which  is  not  normally  legal).  Before sendmail
         will access the database, it checks to insure  that
         this entry exists[11].

      2.6.3.  List owners

              If  an  error  occurs  on sending to a certain
         address, say "x", sendmail will look for  an  alias
         of  the form "owner-x" to receive the errors.  This
         is typically useful for a mailing  list  where  the
         submitter of the list has no control over the main-
         tenance of the list itself; in this case  the  list
         maintainer  would  be  the  owner of the list.  For
         example:

             unix-wizards: eric@ucbarpa, wnj@monet, nosuchuser,
                  sam@matisse
             owner-unix-wizards: unix-wizards-request
             unix-wizards-request: eric@ucbarpa

         would cause "eric@ucbarpa" to get  the  error  that
         will  occur  when someone sends to unix-wizards due
         to the inclusion of "nosuchuser" on the list.
____________________
   [11]The AliasWait option is required in the configuration
for this action to occur.  This should  normally  be  speci-
fied.












SMM:08-30          Sendmail Installation and Operation Guide


              List owners also  cause  the  envelope  sender
         address  to be modified.  The contents of the owner
         alias are used if they point to a single user, oth-
         erwise  the  name of the alias itself is used.  For
         this reason, and to obey Internet conventions,  the
         "owner-"  address normally points at the "-request"
         address; this causes messages to go  out  with  the
         typical   Internet   convention  of  using  ``list-
         request'' as the return address.

   2.7.  User Information Database

           This option is deprecated, use virtusertable  and
      genericstable  instead  as explained in cf/README.  If
      you have a version of sendmail with the user  informa-
      tion  database compiled in, and you have specified one
      or more databases using the U  option,  the  databases
      will be searched for a user:maildrop entry.  If found,
      the mail will be sent to the specified address.

   2.8.  Per-User Forwarding (.forward Files)

           As an alternative to the alias database, any user
      may  put a file with the name ".forward" in his or her
      home directory.  If this file exists,  sendmail  redi-
      rects  mail  for  that  user  to the list of addresses
      listed in the .forward file.  Note  that  aliases  are
      fully  expanded  before  forward files are referenced.
      For example, if the home directory for user "mckusick"
      has a .forward file with contents:

          mckusick@ernie
          kirk@calder

      then  any  mail  arriving for "mckusick" will be redi-
      rected to the specified accounts.

           Actually,  the  configuration  file   defines   a
      sequence  of  filenames to check.  By default, this is
      the user's .forward file, but can  be  defined  to  be
      more  generally  using the ForwardPath option.  If you
      change this, you will have to inform your user base of
      the  change; .forward is pretty well incorporated into
      the collective subconscious.

   2.9.  Special Header Lines

           Several header lines have special interpretations
      defined by the configuration file.  Others have inter-
      pretations built into sendmail that cannot be  changed
      without   changing  the  code.   These  built-ins  are
      described here.











Sendmail Installation and Operation Guide          SMM:08-31


      2.9.1.  Errors-To:

              If errors occur  anywhere  during  processing,
         this  header will cause error messages to go to the
         listed addresses.  This  is  intended  for  mailing
         lists.

              The  Errors-To:  header was created in the bad
         old days when UUCP didn't understand  the  distinc-
         tion  between  an envelope and a header; this was a
         hack to provide what should now be  passed  as  the
         envelope sender address.  It should go away.  It is
         only used if the UseErrorsTo option is set.

              The Errors-To: header is officially deprecated
         and will go away in a future release.

      2.9.2.  Apparently-To:

              RFC  822 requires at least one recipient field
         (To:, Cc:, or Bcc: line) in every  message.   If  a
         message  comes  in with no recipients listed in the
         message then sendmail will adjust the header  based
         on the "NoRecipientAction" option.  One of the pos-
         sible actions is to add an "Apparently-To:"  header
         line for any recipients it is aware of.

              The  Apparently-To: header is non-standard and
         is both deprecated and strongly discouraged.

      2.9.3.  Precedence

              The Precedence: header can be used as a  crude
         control  of  message  priority.  It tweaks the sort
         order in the queue and can be configured to  change
         the  message  timeout  values.  The precedence of a
         message also controls how delivery status notifica-
         tions (DSNs) are processed for that message.

   2.10.  IDENT Protocol Support

           Sendmail  supports  the IDENT protocol as defined
      in RFC 1413.  Note that the RFC states a client should
      wait  at least 30 seconds for a response.  The default
      Timeout.ident is 5 seconds as many sites have  adopted
      the practice of dropping IDENT queries.  This has lead
      to delays processing  mail.   Although  this  enhances
      identification  of  the  author of an email message by
      doing a ``call back'' to  the  originating  system  to
      include  the  owner  of a particular TCP connection in
      the audit trail it is in no sense  perfect;  a  deter-
      mined forger can easily spoof the IDENT protocol.  The
      following description is excerpted from RFC 1413:










SMM:08-32          Sendmail Installation and Operation Guide


           6.  Security Considerations

           The information returned by this protocol  is  at
           most  as  trustworthy as the host providing it OR
           the organization operating the host.   For  exam-
           ple,  a PC in an open lab has few if any controls
           on it to prevent a user from having this protocol
           return  any identifier the user wants.  Likewise,
           if the host has been compromised the  information
           returned may be completely erroneous and mislead-
           ing.

           The Identification Protocol is not intended as an
           authorization  or  access  control  protocol.  At
           best, it provides some additional auditing infor-
           mation  with  respect  to  TCP  connections.   At
           worst, it can provide misleading,  incorrect,  or
           maliciously incorrect information.

           The  use of the information returned by this pro-
           tocol for other than auditing  is  strongly  dis-
           couraged.    Specifically,  using  Identification
           Protocol information to make access control deci-
           sions  -  either  as the primary method (i.e., no
           other checks) or as an adjunct to  other  methods
           may  result  in  a weakening of normal host secu-
           rity.

           An Identification server may  reveal  information
           about users, entities, objects or processes which
           might normally be considered private.  An Identi-
           fication server provides service which is a rough
           analog of the CallerID services provided by  some
           phone companies and many of the same privacy con-
           siderations and arguments that apply to the  Cal-
           lerID  service  apply  to Identification.  If you
           wouldn't run a "finger"  server  due  to  privacy
           considerations  you may not want to run this pro-
           tocol.

      In some cases your system may not work  properly  with
      IDENT  support  due to a bug in the TCP/IP implementa-
      tion.  The symptoms will be that for  some  hosts  the
      SMTP connection will be closed almost immediately.  If
      this is true or if you do not want to use  IDENT,  you
      should  set  the IDENT timeout to zero; this will dis-
      able the IDENT protocol.

3.  ARGUMENTS

        The  complete  list  of  arguments  to  sendmail  is
   described  in detail in Appendix A.  Some important argu-
   ments are described here.










Sendmail Installation and Operation Guide          SMM:08-33


   3.1.  Queue Interval

           The amount of time between forking a  process  to
      run  through  the queue is defined by the -q flag.  If
      you run with delivery mode set to i or b this  can  be
      relatively  large, since it will only be relevant when
      a host that was down comes back up.  If you run  in  q
      mode  it  should be relatively short, since it defines
      the maximum amount of time that a message may  sit  in
      the queue.  (See also the MinQueueAge option.)

           RFC  1123  section  5.3.1.1  says that this value
      should be at least 30 minutes (although that  probably
      doesn't make sense if you use ``queue-only'' mode).

           Notice:  the meaning of the interval time depends
      on whether normal queue runners  or  persistent  queue
      runners  are  used.   For  the  former, it is the time
      between subsequent starts of a  queue  run.   For  the
      latter,  it is the time sendmail waits after a persis-
      tent queue runner has finished its work to  start  the
      next  one.   Hence  for  persistent queue runners this
      interval should be very low, typically  no  more  than
      two minutes.

   3.2.  Daemon Mode

           If  you  allow  incoming mail over an IPC connec-
      tion, you should have a daemon running.   This  should
      be  set  by your /etc/rc file using the -bd flag.  The
      -bd flag and the -q flag may be combined in one call:

          /usr/sbin/sendmail -bd -q30m


           An alternative approach  is  to  invoke  sendmail
      from  inetd(8)  (use the -bs -Am flags to ask sendmail
      to speak SMTP on its standard input and output and  to
      run  as MTA).  This works and allows you to wrap send-
      mail in a TCP wrapper program, but may be a bit slower
      since  the  configuration  file  has  to be re-read on
      every message that comes in.   If  you  do  this,  you
      still  need  to  have  a sendmail running to flush the
      queue:

          /usr/sbin/sendmail -q30m


   3.3.  Forcing the Queue

           In some cases you may find  that  the  queue  has
      gotten clogged for some reason.  You can force a queue
      run  using  the  -q  flag  (with  no  value).   It  is










SMM:08-34          Sendmail Installation and Operation Guide


      entertaining to use the -v flag (verbose) when this is
      done to watch what happens:

          /usr/sbin/sendmail -q -v


           You can also limit the jobs to those with a  par-
      ticular  queue identifier, recipient, sender, or queue
      group using one of the queue modifiers.  For  example,
      "-qRberkeley"  restricts  the  queue  run to jobs that
      have the string "berkeley" somewhere  in  one  of  the
      recipient  addresses.   Similarly,  "-qSstring" limits
      the run to particular senders, "-qIstring"  limits  it
      to  particular queue identifiers, and "-qGstring" lim-
      its it to a particular queue group.  The  named  queue
      group will be run even if it is set to have 0 runners.
      You may also place an !  before the I or  R  or  S  to
      indicate that jobs are limited to not including a par-
      ticular queue identifier, recipient  or  sender.   For
      example,  "-q!Rseattle"  limits  the queue run to jobs
      that do not have the string "seattle" somewhere in one
      of the recipient addresses.  Should you need to termi-
      nate the queue jobs currently active then a SIGTERM to
      the  parent of the process (or processes) will cleanly
      stop the jobs.

   3.4.  Debugging

           There are a fairly large number  of  debug  flags
      built  into  sendmail.  Each debug flag has a category
      and a level.  Higher  levels  increase  the  level  of
      debugging activity; in most cases, this means to print
      out more information.  The convention is  that  levels
      greater  than  nine are "absurd," i.e., they print out
      so much information that you wouldn't normally want to
      see them except for debugging that particular piece of
      code.

           You should never run a production sendmail server
      in debug mode.  Many of the debug flags will result in
      debug output being sent over the SMTP  channel.   This
      will confuse many mail programs.  However, for testing
      purposes, it can be useful when sending mail  manually
      via  telnet to the port you are using while debugging.

           A debug category is either an integer,  like  42,
      or  a  name,  like  ANSI.   You can specify a range of
      numeric debug categories using the syntax 17-42.   You
      can  specify  a  set of named debug categories using a
      glob pattern like "sm_trace_*".  At present, only  "*"
      and "?"  are supported in these glob patterns.












Sendmail Installation and Operation Guide          SMM:08-35


           Debug flags are set using the -d option; the syn-
      tax is:

          debug-flag:        -d debug-list
          debug-list:        debug-option [ , debug-option ]*
          debug-option:      debug-categories [ . debug-level ]
          debug-categories:  integer | integer - integer | category-pattern
          category-pattern:  [a-zA-Z_*?][a-zA-Z0-9_*?]*
          debug-level:       integer

      where spaces are for reading ease only.  For example,

          -d12               Set category 12 to level 1
          -d12.3             Set category 12 to level 3
          -d3-17             Set categories 3 through 17 to level 1
          -d3-17.4           Set categories 3 through 17 to level 4
          -dANSI             Set category ANSI to level 1
          -dsm_trace_*.3     Set all named categories matching sm_trace_* to level 3

      For a complete list of the available debug  flags  you
      will  have to look at the code and the TRACEFLAGS file
      in the sendmail distribution (they are too dynamic  to
      keep  this  document up to date).  For a list of named
      debug categories in the sendmail binary, use

          ident /usr/sbin/sendmail | grep Debug


   3.5.  Changing the Values of Options

           Options can be overridden using the -o or -O com-
      mand line flags.  For example,

          /usr/sbin/sendmail -oT2m

      sets  the  T  (timeout) option to two minutes for this
      run only; the equivalent line using  the  long  option
      name is

          /usr/sbin/sendmail -OTimeout.queuereturn=2m


           Some  options  have security implications.  Send-
      mail allows you to set  these,  but  relinquishes  its
      set-user-ID   or   set-group-ID   permissions   there-
      after[12].
____________________
   [12]That is, it sets its effective uid to the  real  uid;
thus,  if  you are executing as root, as from root's crontab
file or during system  startup  the  root  permissions  will
still be honored.












SMM:08-36          Sendmail Installation and Operation Guide


   3.6.  Trying a Different Configuration File

           An  alternative  configuration file can be speci-
      fied using the -C flag; for example,

          /usr/sbin/sendmail -Ctest.cf -oQ/tmp/mqueue

      uses the configuration file  test.cf  instead  of  the
      default  /etc/mail/sendmail.cf.  If the -C flag has no
      value it defaults to sendmail.cf in the current direc-
      tory.

           Sendmail  gives  up  set-user-ID root permissions
      (if it has been installed set-user-ID root)  when  you
      use  this  flag,  so  it  is  common to use a publicly
      writable directory (such as /tmp) as the queue  direc-
      tory (QueueDirectory or Q option) while testing.

   3.7.  Logging Traffic

           Many  SMTP implementations do not fully implement
      the protocol.  For  example,  some  personal  computer
      based  SMTPs  do  not understand continuation lines in
      reply codes.  These can be very hard to trace.  If you
      suspect  such  a  problem, you can set traffic logging
      using the -X flag.  For example,

          /usr/sbin/sendmail -X /tmp/traffic -bd

      will log all traffic in the file /tmp/traffic.

           This logs a lot of data very quickly  and  should
      NEVER  be used during normal operations.  After start-
      ing up such a daemon, force the errant  implementation
      to  send  a message to your host.  All message traffic
      in and out of sendmail, including  the  incoming  SMTP
      traffic, will be logged in this file.

   3.8.  Testing Configuration Files

           When  you build a configuration table, you can do
      a certain amount of testing using the "test  mode"  of
      sendmail.  For example, you could invoke sendmail as:

          sendmail -bt -Ctest.cf

      which  would read the configuration file "test.cf" and
      enter test mode.  In this mode, you enter lines of the
      form:

          rwset address

      where  rwset  is the rewriting set you want to use and










Sendmail Installation and Operation Guide          SMM:08-37


      address is an address to apply the set to.  Test  mode
      shows  you  the steps it takes as it proceeds, finally
      showing you the address it ends up with.  You may  use
      a comma separated list of rwsets for sequential appli-
      cation of rules to an input.  For example:

          3,1,21,4 monet:bollard

      first applies ruleset three to the  input  "monet:bol-
      lard."   Ruleset  one is then applied to the output of
      ruleset three, followed similarly by rulesets  twenty-
      one and four.

           If  you  need  more  detail, you can also use the
      "-d21" flag to turn on more debugging.  For example,

          sendmail -bt -d21.99

      turns on an incredible amount of information; a single
      word  address  is  probably going to print out several
      pages worth of information.

           You should be warned  that  internally,  sendmail
      applies  ruleset 3 to all addresses.  In test mode you
      will have to do that  manually.   For  example,  older
      versions allowed you to use

          0 bruce@broadcast.sony.com

      This version requires that you use:

          3,0 bruce@broadcast.sony.com


           As of version 8.7, some other syntaxes are avail-
      able in test mode:

      .Dxvalue  defines macro x to have the indicated value.
                This is useful when debugging rules that use
                the $&x syntax.

      .Ccvalue  adds the indicated value to class c.

      =Sruleset dumps the contents of the indicated ruleset.

      -ddebug-spec
                is equivalent to the command-line flag.

      Version 8.9 introduced more features:

      ?         shows a help message.












SMM:08-38          Sendmail Installation and Operation Guide


      =M        display the known mailers.

      $m        print the value of macro m.

      $=c       print the contents of class c.

      /mx host  returns the MX records for `host'.

      /parse address
                parse address, returning the value of crack-
                addr, and the parsed address.

      /try mailer addr
                rewrite address into the form it  will  have
                when presented to the indicated mailer.

      /tryflags flags
                set flags used by parsing.  The flags can be
                `H' for Header or `E' for Envelope, and  `S'
                for  Sender or `R' for Recipient.  These can
                be combined,  `HR'  sets  flags  for  header
                recipients.

      /canon hostname
                try to canonify hostname.

      /map mapname key
                look up `key' in the indicated `mapname'.

      /quit     quit address test mode.

   3.9.  Persistent Host Status Information

           When  HostStatusDirectory is enabled, information
      about the status of hosts is maintained  on  disk  and
      can thus be shared between different instantiations of
      sendmail.  The status of the last connection with each
      remote host may be viewed with the command:

          sendmail -bh

      This information may be flushed with the command:

          sendmail -bH

      Flushing  the  information  prevents new sendmail pro-
      cesses from loading it, but does not prevent  existing
      processes  from using the status information that they
      already have.














Sendmail Installation and Operation Guide          SMM:08-39


4.  TUNING

        There are a number of configuration  parameters  you
   may want to change, depending on the requirements of your
   site.  Most of these are set using an option in the  con-
   figuration   file.    For  example,  the  line  "O  Time-
   out.queuereturn=5d" sets option "Timeout.queuereturn"  to
   the value "5d" (five days).

        Most  of these options have appropriate defaults for
   most sites.  However, sites having very high  mail  loads
   may  find they need to tune them as appropriate for their
   mail load.  In particular,  sites  experiencing  a  large
   number  of small messages, many of which are delivered to
   many recipients, may find that they need  to  adjust  the
   parameters dealing with queue priorities.

        All  versions  of  sendmail  prior to 8.7 had single
   character option names.  As of  8.7,  options  have  long
   (multi-character  names).   Although  old short names are
   still accepted, most new options do not have short equiv-
   alents.

        This section only describes the options you are most
   likely to want to tweak; read section 5 for more details.

   4.1.  Timeouts

           All time intervals are set using a scaled syntax.
      For example, "10m"  represents  ten  minutes,  whereas
      "2h30m" represents two and a half hours.  The full set
      of scales is:

          s   seconds
          m   minutes
          h   hours
          d   days
          w   weeks


      4.1.1.  Queue interval

              The argument to  the  -q  flag  specifies  how
         often  a  sub-daemon  will  run the queue.  This is
         typically set to between fifteen  minutes  and  one
         hour.   If  not set, or set to zero, the queue will
         not be run automatically.  RFC 1123 section 5.3.1.1
         recommends  that  this  be  at  least  30  minutes.
         Should you need to terminate the  queue  jobs  cur-
         rently  active  then a SIGTERM to the parent of the
         process (or processes) will cleanly stop the  jobs.












SMM:08-40          Sendmail Installation and Operation Guide


      4.1.2.  Read timeouts

              Timeouts all have option names "Timeout.subop-
         tion".  Most of these control SMTP operations.  The
         recognized  suboptions,  their  default values, and
         the minimum values  allowed  by  RFC  2821  section
         4.5.3.2 (or RFC 1123 section 5.3.2) are:

         connect   The  time  to wait for an SMTP connection
                   to open (the connect(2) system call)  [0,
                   unspecified].   If  zero, uses the kernel
                   default.  In  no  case  can  this  option
                   extend the timeout longer than the kernel
                   provides, but it can shorten it.  This is
                   to  get  around  kernels  that provide an
                   absurdly long connection timeout (90 min-
                   utes in one case).

         iconnect  The  same  as  connect, except it applies
                   only to the initial attempt to connect to
                   a  host  for a given message [0, unspeci-
                   fied].  The concept is that  this  should
                   be very short (a few seconds); hosts that
                   are well connected  and  responsive  will
                   thus be serviced immediately.  Hosts that
                   are slow will not hold up other  deliver-
                   ies in the initial delivery attempt.

         aconnect  [0,   unspecified]  The  overall  timeout
                   waiting for all connection for  a  single
                   delivery  attempt  to  succeed.  If 0, no
                   overall limit is applied.   This  can  be
                   used to restrict the total amount of time
                   trying to connect to a long list of  host
                   that  could  accept  an  e-mail  for  the
                   recipient.  This timeout does  not  apply
                   to  FallbackMXhost,  i.e., if the time is
                   exhausted, the  FallbackMXhost  is  tried
                   next.

         initial   The  wait  for  the  initial 220 greeting
                   message [5m, 5m].

         helo      The wait for a reply from a HELO or  EHLO
                   command   [5m,  unspecified].   This  may
                   require a host name lookup, so five  min-
                   utes is probably a reasonable minimum.

         mail*     The  wait for a reply from a MAIL command
                   [10m, 5m].

         rcpt*     The wait for a reply from a RCPT  command
                   [1h, 5m].  This should be long because it










Sendmail Installation and Operation Guide          SMM:08-41


                   could be pointing at a list that takes  a
                   long time to expand (see below).

         datainit* The  wait for a reply from a DATA command
                   [5m, 2m].

         datablock*#
                   The wait for reading a data  block  (that
                   is,  the body of the message).  [1h, 3m].
                   This  should  be  long  because  it  also
                   applies to programs piping input to send-
                   mail which have no guarantee  of  prompt-
                   ness.

         datafinal*
                   The  wait for a reply from the dot termi-
                   nating a message.  [1h, 10m].  If this is
                   shorter than the time actually needed for
                   the  receiver  to  deliver  the  message,
                   duplicates  will  be  generated.  This is
                   discussed in RFC 1047.

         rset      The wait for a reply from a RSET  command
                   [5m, unspecified].

         quit      The  wait for a reply from a QUIT command
                   [2m, unspecified].

         misc      The wait for a reply  from  miscellaneous
                   (but  short)  commands  such as NOOP (no-
                   operation)  and  VERB  (go  into  verbose
                   mode).  [2m, unspecified].

         command*# In  server  SMTP,  the  time  to wait for
                   another command.  [1h, 5m].

         ident#    The timeout waiting for  a  reply  to  an
                   IDENT query [5s[13], unspecified].

         lhlo      The wait for a reply to an LMTP LHLO com-
                   mand [2m, unspecified].

         auth      The  timeout  for a reply in an SMTP AUTH
                   dialogue [10m, unspecified].

         starttls  The timeout for a reply to an SMTP START-
                   TLS  command  and  the TLS handshake [1h,
                   unspecified].
____________________
   [13]On  some systems the default is zero to turn the pro-
tocol off entirely.












SMM:08-42          Sendmail Installation and Operation Guide


         fileopen# The  timeout  for  opening  .forward  and
                   :include: files [60s, none].

         control#  The timeout for a complete control socket
                   transaction to complete [2m, none].

         hoststatus#
                   How long status information about a  host
                   (e.g.,  host  down) will be cached before
                   it is  considered  stale  [30m,  unspeci-
                   fied].

         resolver.retrans#
                   The resolver's retransmission time inter-
                   val (in  seconds)  [varies].   Sets  both
                   Timeout.resolver.retrans.first  and Time-
                   out.resolver.retrans.normal.

         resolver.retrans.first#
                   The resolver's retransmission time inter-
                   val (in seconds) for the first attempt to
                   deliver a message [varies].

         resolver.retrans.normal#
                   The resolver's retransmission time inter-
                   val (in seconds) for all resolver lookups
                   except   the   first   delivery   attempt
                   [varies].

         resolver.retry#
                   The  number  of  times  to  retransmit  a
                   resolver   query.    Sets   both    Time-
                   out.resolver.retry.first     and    Time-
                   out.resolver.retry.normal [varies].

         resolver.retry.first#
                   The  number  of  times  to  retransmit  a
                   resolver  query  for the first attempt to
                   deliver a message [varies].

         resolver.retry.normal#
                   The  number  of  times  to  retransmit  a
                   resolver query for all resolver lookups
                    except   the   first   delivery  attempt
                   [varies].

         For compatibility with old configuration files,  if
         no  suboption is specified, all the timeouts marked
         with an asterick  (*)  are  set  to  the  indicated
         value.   All but those marked with a pound sign (#)
         apply to client SMTP.












Sendmail Installation and Operation Guide          SMM:08-43


              For example, the lines:

             O Timeout.command=25m
             O Timeout.datablock=3h

         sets the server SMTP command timeout to 25  minutes
         and the input data block timeout to three hours.

      4.1.3.  Message timeouts

              After  sitting in the queue for a few days, an
         undeliverable message will time out.   This  is  to
         insure  that  at  least  the sender is aware of the
         inability to send a message.  The timeout is  typi-
         cally set to five days.  It is sometimes considered
         convenient to also send a warning  message  if  the
         message  is  in  the  queue longer than a few hours
         (assuming you normally have good  connectivity;  if
         your  messages  normally took several hours to send
         you wouldn't want to do this because it wouldn't be
         an  unusual  event).   These timeouts are set using
         the   Timeout.queuereturn   and   Timeout.queuewarn
         options  in the configuration file (previously both
         were set using the T option).

              If the message is submitted using  the  NOTIFY
         SMTP  extension, warning messages will only be sent
         if NOTIFY=DELAY is specified.  The queuereturn  and
         queuewarn  timeouts can be further qualified with a
         tag based on the Precedence: field in the  message;
         they must be one of "urgent" (indicating a positive
         non-zero precedence) "normal"  (indicating  a  zero
         precedence),  or  "non-urgent" (indicating negative
         precedences).  For example, setting "Timeout.queue-
         warn.urgent=1h" sets the warning timeout for urgent
         messages only to  one  hour.   The  default  if  no
         precedence  is  indicated is to set the timeout for
         all precedences.  The value "now" can be  used  for
         -O  Timeout.queuereturn  to  return entries immedi-
         ately during a queue run, e.g., to bounce  messages
         independent of their time in the queue.

              Since  these options are global, and since you
         cannot know a priori how long another host  outside
         your  domain  will  be  down, a five day timeout is
         recommended.  This allows a recipient  to  fix  the
         problem  even  if  it  occurs at the beginning of a
         long weekend.  RFC 1123 section 5.3.1.1  says  that
         this parameter should be ``at least 4-5 days''.

              The Timeout.queuewarn value can be piggybacked
         on the T option by indicating a time after which  a
         warning  message  should  be sent; the two timeouts










SMM:08-44          Sendmail Installation and Operation Guide


         are separated by a slash.  For example, the line

             OT5d/4h

         causes email to fail after five days, but a warning
         message will be sent after four hours.  This should
         be large enough that the  message  will  have  been
         tried several times.

   4.2.  Forking During Queue Runs

           By  setting  the ForkEachJob (Y) option, sendmail
      will fork before each individual message while running
      the queue.  This option was used with earlier releases
      to prevent sendmail from consuming  large  amounts  of
      memory.   It  should no longer be necessary with send-
      mail 8.12.  If the  ForkEachJob  option  is  not  set,
      sendmail will keep track of hosts that are down during
      a queue run, which can  improve  performance  dramati-
      cally.

           If the ForkEachJob option is set, sendmail cannot
      use connection caching.

   4.3.  Queue Priorities

           Every message is assigned a priority when  it  is
      first instantiated, consisting of the message size (in
      bytes) offset by the message class  (which  is  deter-
      mined  from  the  Precedence:  header) times the "work
      class factor" and the number of recipients  times  the
      "work  recipient  factor."   The  priority  is used to
      order the queue.  Higher numbers for the priority mean
      that  the message will be processed later when running
      the queue.

           The message size is included so that  large  mes-
      sages  are  penalized relative to small messages.  The
      message class allows users  to  send  "high  priority"
      messages  by  including a "Precedence:" field in their
      message; the value of this field is looked up in the P
      lines  of the configuration file.  Since the number of
      recipients  affects  the  amount  of  load  a  message
      presents to the system, this is also included into the
      priority.

           The recipient and class factors can be set in the
      configuration  file  using the RecipientFactor (y) and
      ClassFactor (z) options respectively.  They default to
      30000  (for  the  recipient  factor) and 1800 (for the
      class factor).  The initial priority is:












Sendmail Installation and Operation Guide          SMM:08-45


     pri=msgsize-(classxClassFactor)+(nrcptxRecipientFactor)

      (Remember, higher values for this  parameter  actually
      mean  that  the  job will be treated with lower prior-
      ity.)

           The priority of a job can also be  adjusted  each
      time it is processed (that is, each time an attempt is
      made to deliver it) using the "work time factor,"  set
      by  the  RetryFactor (Z) option.  This is added to the
      priority, so it normally decreases the  precedence  of
      the  job,  on  the  grounds that jobs that have failed
      many times will tend to fail again in the future.  The
      RetryFactor option defaults to 90000.

   4.4.  Load Limiting

           Sendmail  can be asked to queue (but not deliver)
      mail if the system load average gets  too  high  using
      the QueueLA (x) option.  When the load average exceeds
      the value of the QueueLA option, the delivery mode  is
      set  to  q  (queue only) if the QueueFactor (q) option
      divided by the difference in the current load  average
      and  the QueueLA option plus one is less than the pri-
      ority of the message -- that is, the message is queued
      iff:

                        pri>LQueueFactor_

      The  QueueFactor  option  defaults  to 600000, so each
      point of load average is worth 600000 priority  points
      (as described above).

           For   drastic  cases,  the  RefuseLA  (X)  option
      defines a load average at which sendmail  will  refuse
      to  accept  network  connections.   Locally  generated
      mail, i.e., mail  which  is  not  submitted  via  SMTP
      (including  incoming  UUCP  mail),  is still accepted.
      Notice that the MSP submits mail to the MTA via  SMTP,
      and  hence  mail will be queued in the client queue in
      such a case.  Therefore it is  necessary  to  run  the
      client mail queue periodically.

   4.5.  Resource Limits

           Sendmail   has   several  parameters  to  control
      resource usage.  Besides those mentionted in the  pre-
      vious  section,  there are at least MaxDaemonChildren,
      ConnectionRateThrottle, MaxQueueChildren, and  MaxRun-
      nersPerQueue.   The  latter  two  limit  the number of
      sendmail processes that operate on the  queue.   These
      are  discussed  in  the section ``Queue Group Declara-
      tion''.  The former two  can  be  used  to  limit  the










SMM:08-46          Sendmail Installation and Operation Guide


      number  of  incoming  connections.   Their appropriate
      values depend on the host  operating  system  and  the
      hardware,  e.g., amount of memory.  In many situations
      it might be useful to set limits to  prevent  to  have
      too many sendmail processes, however, these limits can
      be abused to mount a denial of  service  attack.   For
      example,  if  MaxDaemonChildren=10  then  an  attacker
      needs to open only 10 SMTP  sessions  to  the  server,
      leave them idle for most of the time, and no more con-
      nections will be accepted.

   4.6.  Delivery Mode

           There are a number of delivery modes  that  send-
      mail  can operate in, set by the DeliveryMode (d) con-
      figuration option.  These modes  specify  how  quickly
      mail will be delivered.  Legal modes are:

          i   deliver interactively (synchronously)
          b   deliver in background (asynchronously)
          q   queue only (don't deliver)
          d   defer delivery attempts (don't deliver)

      There  are  tradeoffs.   Mode "i" gives the sender the
      quickest feedback, but may slow down some mailers  and
      is  hardly ever necessary.  Mode "b" delivers promptly
      but can cause large numbers of processes if you have a
      mailer  that  takes  a long time to deliver a message.
      Mode "q" minimizes the load on your machine, but means
      that  delivery  may  be  delayed  for  up to the queue
      interval.  Mode "d" is identical to  mode  "q"  except
      that it also prevents lookups in maps including the -D
      flag from working during the initial queue  phase;  it
      is  intended  for  ``dial  on demand'' sites where DNS
      lookups might cost real money.  Some simple error mes-
      sages  (e.g.,  host  unknown during the SMTP protocol)
      will be delayed using this  mode.   Mode  "b"  is  the
      usual default.

           If you run in mode "q" (queue only), "d" (defer),
      or "b"  (deliver  in  background)  sendmail  will  not
      expand  aliases and follow .forward files upon initial
      receipt of the mail.  This speeds up the  response  to
      RCPT  commands.   Mode  "i"  should not be used by the
      SMTP server.

   4.7.  Log Level

           The level of logging can  be  set  for  sendmail.
      The  default  using  a standard configuration table is
      level 9.  The levels are as follows:












Sendmail Installation and Operation Guide          SMM:08-47


      0    Minimal logging.

      1    Serious system failures  and  potential  security
           problems.

      2    Lost communications (network problems) and proto-
           col failures.

      3    Other  serious  failures,  malformed   addresses,
           transient   forward/include   errors,  connection
           timeouts.

      4    Minor failures, out of date alias databases, con-
           nection rejections via check_ rulesets.

      5    Message collection statistics.

      6    Creation  of  error  messages, VRFY and EXPN com-
           mands.

      7    Delivery failures (host or user unknown, etc.).

      8    Successful   deliveries   and   alias    database
           rebuilds.

      9    Messages  being  deferred  (due  to  a host being
           down, etc.).

      10   Database expansion (alias,  forward,  and  userdb
           lookups) and authentication information.

      11   NIS errors and end of job processing.

      12   Logs all SMTP connections.

      13   Log  bad user shells, files with improper permis-
           sions, and other questionable situations.

      14   Logs refused connections.

      15   Log all incoming and outgoing SMTP commands.

      20   Logs attempts to run locked queue  files.   These
           are not errors, but can be useful to note if your
           queue appears to be clogged.

      30   Lost  locks  (only  if  using  lockf  instead  of
           flock).

      Additionally,   values   above  64  are  reserved  for
      extremely verbose debugging output.   No  normal  site
      would ever set these.











SMM:08-48          Sendmail Installation and Operation Guide


   4.8.  File Modes

           The modes used for files depend on what function-
      ality you want and the level of security you  require.
      In  many  cases  sendmail does careful checking of the
      modes of files and  directories  to  avoid  accidental
      compromise;  if  you  want to make it possible to have
      group-writable support files you may need to  use  the
      DontBlameSendmail  option  to  turn  off some of these
      checks.

      4.8.1.  To suid or not to suid?

              Sendmail is no longer installed set-user-ID to
         root.   sendmail/SECURITY explains how to configure
         and install sendmail without  set-user-ID  to  root
         but set-group-ID which is the default configuration
         starting with 8.12.

              The daemon usually runs as root, unless  other
         measures are taken.  At the point where sendmail is
         about to exec(2) a mailer, it checks to see if  the
         userid  is zero (root); if so, it resets the userid
         and groupid to a default (set by the U=  equate  in
         the  mailer  line; if that is not set, the Default-
         User option is used).  This can  be  overridden  by
         setting  the  S flag to the mailer for mailers that
         are trusted and must be called as  root.   However,
         this  will  cause  mail  processing to be accounted
         (using sa(8)) to root rather than to the user send-
         ing the mail.

              A  middle  ground  is  to  set  the  RunAsUser
         option.  This causes sendmail to become  the  indi-
         cated  user as soon as it has done the startup that
         requires root privileges  (primarily,  opening  the
         SMTP  socket).   If  you  use  RunAsUser, the queue
         directory (normally  /var/spool/mqueue)  should  be
         owned  by  that  user,  and all files and databases
         (including  user  .forward  files,   alias   files,
         :include:  files,  and  external databases) must be
         readable by that user.  Also, since  sendmail  will
         not be able to change its uid, delivery to programs
         or files will be marked as unsafe, e.g., undeliver-
         able,  in  .forward,  aliases, and :include: files.
         Administrators can override  this  by  setting  the
         DontBlameSendmail  option  to  the setting NonRoot-
         SafeAddr.  RunAsUser is probably  best  suited  for
         firewall  configurations  that  don't  have regular
         user logins.  If the option is  used  on  a  system
         which  performs  local  delivery,  then  the  local
         delivery agent must  have  the  proper  permissions
         (i.e.,  usually  set-user-ID root) since it will be










Sendmail Installation and Operation Guide          SMM:08-49


         invoked by the RunAsUser, not by root.

      4.8.2.  Turning off security checks

              Sendmail is very particular about the modes of
         files  that  it  reads  or writes.  For example, by
         default it will refuse to read most files that  are
         group  writable on the grounds that they might have
         been tampered with by someone other than the owner;
         it will even refuse to read files in group writable
         directories.  Also, sendmail will refuse to  create
         a new aliases database in an unsafe directory.  You
         can get around this by manually creating the  data-
         base  file as a trusted user ahead of time and then
         rebuilding the aliases database with newaliases.

              If you are quite sure that your  configuration
         is  safe and you want sendmail to avoid these secu-
         rity checks, you can turn off certain checks  using
         the  DontBlameSendmail  option.   This option takes
         one or more names  that  disable  checks.   In  the
         descriptions  that follow, "unsafe directory" means
         a directory that is writable by anyone  other  than
         the owner.  The values are:

         Safe No special handling.

         AssumeSafeChown
              Assume   that   the   chown   system  call  is
              restricted to root.  Since  some  versions  of
              UNIX  permit  regular users to give away their
              files to  other  users  on  some  filesystems,
              sendmail often cannot assume that a given file
              was created by the owner, particularly when it
              is  in a writable directory.  You can set this
              flag  if  you  know  that  file  giveaway   is
              restricted on your system.

         ClassFileInUnsafeDirPath
              When  reading class files (using the F line in
              the configuration file), allow files that  are
              in unsafe directories.

         DontWarnForwardFileInUnsafeDirPath
              Prevent logging of unsafe directory path warn-
              ings for non-existent forward files.

         ErrorHeaderInUnsafeDirPath
              Allow the file named in the ErrorHeader option
              to be in an unsafe directory.

         FileDeliveryToHardLink
              Allow delivery to files that are hard links.










SMM:08-50          Sendmail Installation and Operation Guide


         FileDeliveryToSymLink
              Allow  delivery  to  files  that  are symbolic
              links.

         ForwardFileInGroupWritableDirPath
              Allow .forward files in group writable  direc-
              tories.

         ForwardFileInUnsafeDirPath
              Allow .forward files in unsafe directories.

         ForwardFileInUnsafeDirPathSafe
              Allow  a  .forward  file  that is in an unsafe
              directory to include references to program and
              files.

         GroupReadableKeyFile
              Accept a group-readable key file for STARTTLS.

         GroupReadableSASLDBFile
              Accept a group-readable  Cyrus  SASL  password
              file.

         GroupWritableAliasFile
              Allow group-writable alias files.

         GroupWritableDirPathSafe
              Change the definition of "unsafe directory" to
              consider  group-writable  directories  to   be
              safe.   World-writable  directories are always
              unsafe.

         GroupWritableForwardFile
              Allow group writable .forward files.

         GroupWritableForwardFileSafe
              Accept group-writable .forward files  as  safe
              for program and file delivery.

         GroupWritableIncludeFile
              Allow group wriable :include: files.

         GroupWritableIncludeFileSafe
              Accept  group-writable :include: files as safe
              for program and file delivery.

         GroupWritableSASLDBFile
              Accept a group-writable  Cyrus  SASL  password
              file.

         HelpFileInUnsafeDirPath
              Allow the file named in the HelpFile option to
              be in an unsafe directory.










Sendmail Installation and Operation Guide          SMM:08-51


         IncludeFileInGroupWritableDirPath
              Allow :include: files in group writable direc-
              tories.

         IncludeFileInUnsafeDirPath
              Allow :include: files in unsafe directories.

         IncludeFileInUnsafeDirPathSafe
              Allow  a  :include:  file that is in an unsafe
              directory to include references to program and
              files.

         InsufficientEntropy
              Try  to  use  STARTTLS  even  if  the PRNG for
              OpenSSL is not  properly  seeded  despite  the
              security problems.

         LinkedAliasFileInWritableDir
              Allow  an  alias  file  that  is  a  link in a
              writable directory.

         LinkedClassFileInWritableDir
              Allow class files that are links  in  writable
              directories.

         LinkedForwardFileInWritableDir
              Allow   .forward   files  that  are  links  in
              writable directories.

         LinkedIncludeFileInWritableDir
              Allow  :include:  files  that  are  links   in
              writable directories.

         LinkedMapInWritableDir
              Allow  map  files  that  are links in writable
              directories.   This  includes  alias  database
              files.

         LinkedServiceSwitchFileInWritableDir
              Allow  the  service  switch  file to be a link
              even if the directory is writable.

         MapInUnsafeDirPath
              Allow maps (e.g., hash, btree, and dbm  files)
              in  unsafe  directories.   This includes alias
              database files.

         NonRootSafeAddr
              Do not mark file  and  program  deliveries  as
              unsafe  if  sendmail  is not running with root
              privileges.












SMM:08-52          Sendmail Installation and Operation Guide


         RunProgramInUnsafeDirPath
              Run programs that are in writable  directories
              without logging a warning.

         RunWritableProgram
              Run programs that are group- or world-writable
              without logging a warning.

         TrustStickyBit
              Allow group or world writable  directories  if
              the  sticky  bit  is set on the directory.  Do
              not set this on systems which do not honor the
              sticky bit on directories.

         WorldWritableAliasFile
              Accept world-writable alias files.

         WorldWritableForwardfile
              Allow world writable .forward files.

         WorldWritableIncludefile
              Allow world wriable :include: files.

         WriteMapToHardLink
              Allow writes to maps that are hard links.

         WriteMapToSymLink
              Allow  writes to maps that are symbolic links.

         WriteStatsToHardLink
              Allow the status file to be a hard link.

         WriteStatsToSymLink
              Allow the status file to be a symbolic link.

   4.9.  Connection Caching

           When processing the queue, sendmail will  try  to
      keep  the  last  few  open  connections  open to avoid
      startup and shutdown costs.  This only applies to  IPC
      connections.

           When  trying  to  open  a connection the cache is
      first searched.  If an open connection is found, it is
      probed  to see if it is still active by sending a RSET
      command.  It is not an error if this  fails;  instead,
      the connection is closed and reopened.

           Two parameters control the connection cache.  The
      ConnectionCacheSize (k) option defines the  number  of
      simultaneous  open connections that will be permitted.
      If it is set to zero, connections will  be  closed  as
      quickly as possible.  The default is one.  This should










Sendmail Installation and Operation Guide          SMM:08-53


      be set as appropriate for your system  size;  it  will
      limit  the  amount  of  system resources that sendmail
      will use during queue runs.   Never  set  this  higher
      than 4.

           The  ConnectionCacheTimeout  (K) option specifies
      the maximum time that any cached  connection  will  be
      permitted  to  idle.   When the idle time exceeds this
      value the connection is closed.  This number should be
      small (under ten minutes) to prevent you from grabbing
      too many resources from other hosts.  The  default  is
      five minutes.

   4.10.  Name Server Access

           Control  of  host  address  lookups is set by the
      hosts service entry in your service switch  file.   If
      you  are  on a system that has built-in service switch
      support (e.g., Ultrix, Solaris,  or  DEC  OSF/1)  then
      your  system  is probably configured properly already.
      Otherwise,   sendmail   will    consult    the    file
      /etc/mail/service.switch,  which  should  be  created.
      Sendmail only uses two  entries:  hosts  and  aliases,
      although   system  routines  may  use  other  services
      (notably the passwd service for user name  lookups  by
      getpwname).

           However, some systems (such as SunOS 4.X) will do
      DNS lookups regardless of the setting of  the  service
      switch entry.  In particular, the system routine geth-
      ostbyname(3) is used to look up host names,  and  many
      vendor  versions try some combination of DNS, NIS, and
      file lookup in /etc/hosts without consulting a service
      switch.  Sendmail makes no attempt to work around this
      problem, and the DNS lookup will be done  anyway.   If
      you  do  not have a nameserver configured at all, such
      as at a UUCP-only site, sendmail will get  a  "connec-
      tion  refused" message when it tries to connect to the
      name server.  If the hosts switch entry has  the  ser-
      vice "dns" listed somewhere in the list, sendmail will
      interpret this to mean a temporary  failure  and  will
      queue  the  mail  for  later processing; otherwise, it
      ignores the name server data.

           The same technique is used to decide  whether  to
      do  MX lookups.  If you want MX support, you must have
      "dns" listed as a service in the hosts switch entry.

           The ResolverOptions  (I)  option  allows  you  to
      tweak  name  server options.  The command line takes a
      series of flags as documented in resolver(3) (with the
      leading  "RES_"  deleted).  Each can be preceded by an
      optional `+' or `-'.  For example, the line










SMM:08-54          Sendmail Installation and Operation Guide


          O ResolverOptions=+AAONLY -DNSRCH

      turns on  the  AAONLY  (accept  authoritative  answers
      only)  and  turns  off  the  DNSRCH (search the domain
      path)  options.   Most  resolver   libraries   default
      DNSRCH,  DEFNAMES, and RECURSE flags on and all others
      off.  If NETINET6 is enabled, most  libraries  default
      to  USE_INET6 as well.  You can also include "HasWild-
      cardMX" to specify that there is a wildcard MX  record
      matching  your domain; this turns off MX matching when
      canonifying names, which  can  lead  to  inappropriate
      canonifications.    Use   "WorkAroundBrokenAAAA"  when
      faced with a broken nameserver that  returns  SERVFAIL
      (a  temporary failure) on T_AAAA (IPv6) lookups during
      hostname canonification.  Notice: it might  be  neces-
      sary  to  apply  the same (or similar) options to sub-
      mit.cf too.

           Version level 1 configurations (see  the  section
      about  Configuration  Version  Level)  turn DNSRCH and
      DEFNAMES off when doing delivery  lookups,  but  leave
      them  on  everywhere  else.   Version  8  of  sendmail
      ignores them when doing canonification  lookups  (that
      is, when using $[ ... $]), and always does the search.
      If you don't want  to  do  automatic  name  extension,
      don't call $[ ... $].

           The  search rules for $[ ... $] are somewhat dif-
      ferent than usual.  If the name being looked up has at
      least  one  dot,  it  always tries the unmodified name
      first.  If that fails, it  tries  the  reduced  search
      path,  and  lastly tries the unmodified name (but only
      for names without a dot, since names with a  dot  have
      already  been  tried).   This  allows  names  such  as
      ``utc.CS'' to match the site in Czechoslovakia  rather
      than  the  site in your local Computer Science depart-
      ment.  It also prefers A and  CNAME  records  over  MX
      records  -- that is, if it finds an MX record it makes
      note of it, but keeps looking.  This way, if you  have
      a wildcard MX record matching your domain, it will not
      assume that all names match.

           To completely turn off all name server access  on
      systems  without service switch support (such as SunOS
      4.X) you will have to  recompile  with  -DNAMED_BIND=0
      and  remove  -lresolv from the list of libraries to be
      searched when linking.

   4.11.  Moving the Per-User Forward Files

           Some sites mount each user's home directory  from
      a  local  disk  on  their  workstation,  so that local
      access is fast.  However, the result is that  .forward










Sendmail Installation and Operation Guide          SMM:08-55


      file  lookups from a central mail server are slow.  In
      some cases, mail can even  be  delivered  on  machines
      inappropriately  because  of a file server being down.
      The performance can be especially bad if you  run  the
      automounter.

           The  ForwardPath  (J)  option allows you to set a
      path of forward files.  For example, the  config  file
      line

          O ForwardPath=/var/forward/$u:$z/.forward.$w

      would  first look for a file with the same name as the
      user's login in /var/forward; if that is not found (or
      is  inaccessible) the file ``.forward.machinename'' in
      the user's home directory is searched.  A  truly  per-
      verse  site  could  also search by sender by using $r,
      $s, or $f.

           If you create a directory such  as  /var/forward,
      it should be mode 1777 (that is, the sticky bit should
      be set).  Users should create  the  files  mode  0644.
      Note  that you must use the ForwardFileInUnsafeDirPath
      and  ForwardFileInUnsafeDirPathSafe  flags  with   the
      DontBlameSendmail  option  to allow forward files in a
      world writable directory.  This might also be used  as
      a denial of service attack (users could create forward
      files for other users); a better approach might be  to
      create  /var/forward  mode 0755 and create empty files
      for each user, owned by that user, mode 0644.  If  you
      do  this,  you don't have to set the DontBlameSendmail
      options indicated above.

   4.12.  Free Space

           On systems that have one of the system  calls  in
      the  statfs(2)  family  (including statvfs and ustat),
      you can specify a minimum number of free blocks on the
      queue  filesystem  using the MinFreeBlocks (b) option.
      If there are fewer than the indicated number of blocks
      free  on  the filesystem on which the queue is mounted
      the SMTP server will reject mail with  the  452  error
      code.   This  invites  the  SMTP  client  to try again
      later.

           Beware of setting this option too  high;  it  can
      cause  rejection of email when that mail would be pro-
      cessed without difficulty.

   4.13.  Maximum Message Size

           To avoid overflowing your  system  with  a  large
      message,  the  MaxMessageSize option can be set to set










SMM:08-56          Sendmail Installation and Operation Guide


      an absolute limit on the  size  of  any  one  message.
      This  will  be  advertised  in  the ESMTP dialogue and
      checked during message collection.

   4.14.  Privacy Flags

           The PrivacyOptions (p) option allows you  to  set
      certain  ``privacy''  flags.   Actually,  many of them
      don't give you any extra privacy, rather just  insist-
      ing  that  client  SMTP  servers  use the HELO command
      before using certain commands or adding extra  headers
      to indicate possible spoof attempts.

           The  option  takes  a  series  of flag names; the
      final privacy is the inclusive or of those flags.  For
      example:

          O PrivacyOptions=needmailhelo, noexpn

      insists that the HELO or EHLO command be used before a
      MAIL command is accepted and disables  the  EXPN  com-
      mand.

           The flags are detailed in section 5.6.

   4.15.  Send to Me Too

           Beginning with version 8.10, sendmail includes by
      default the (envelope) sender in any list  expansions.
      For  example,  if "matt" sends to a list that contains
      "matt" as one of the members he will get a copy of the
      message.   If the MeToo option is set to FALSE (in the
      configuration file or  via  the  command  line),  this
      behavior  is  changed,  i.e., the (envelope) sender is
      excluded in list expansions.

5.  THE WHOLE SCOOP ON THE CONFIGURATION FILE

        This section describes  the  configuration  file  in
   detail.

        There is one point that should be made clear immedi-
   ately: the syntax of the configuration file  is  designed
   to  be reasonably easy to parse, since this is done every
   time sendmail starts up, rather than easy for a human  to
   read  or  write.  The configuration file should be gener-
   ated via the method described in cf/README, it should not
   be  edited  directly  unless someone is familiar with the
   internals of the syntax described here and it is not pos-
   sible  to  achieve  the  desired  result  via the default
   method.












Sendmail Installation and Operation Guide          SMM:08-57


        The configuration file is organized as a  series  of
   lines,  each  of  which  begins  with  a single character
   defining the semantics for the rest of the  line.   Lines
   beginning  with  a  space or a tab are continuation lines
   (although the semantics are  not  well  defined  in  many
   places).   Blank  lines  and lines beginning with a sharp
   symbol (`#') are comments.

   5.1.  R and S -- Rewriting Rules

           The core of address  parsing  are  the  rewriting
      rules.  These are an ordered production system.  Send-
      mail scans through the set of rewriting rules  looking
      for  a  match on the left hand side (LHS) of the rule.
      When a rule matches, the address is  replaced  by  the
      right hand side (RHS) of the rule.

           There  are several sets of rewriting rules.  Some
      of the rewriting sets are  used  internally  and  must
      have  specific semantics.  Other rewriting sets do not
      have specifically assigned semantics, and may be  ref-
      erenced  by the mailer definitions or by other rewrit-
      ing sets.

           The syntax of these two commands are:

          Sn

      Sets the current ruleset being collected to n.  If you
      begin  a  ruleset more than once it appends to the old
      definition.

          Rlhs rhs comments

      The fields must be separated by at least one tab char-
      acter;  there  may  be  embedded spaces in the fields.
      The lhs is a pattern that is applied to the input.  If
      it  matches,  the  input is rewritten to the rhs.  The
      comments are ignored.

           Macro expansions of the  form  $x  are  performed
      when  the configuration file is read.  A literal $ can
      be included using $$.  Expansions of the form $&x  are
      performed  at  run  time using a somewhat less general
      algorithm.  This  is  intended  only  for  referencing
      internally  defined macros such as $h that are changed
      at runtime.

      5.1.1.  The left hand side

              The left hand side of rewriting rules contains
         a   pattern.    Normal  words  are  simply  matched
         directly.  Metasyntax is introduced using a  dollar










SMM:08-58          Sendmail Installation and Operation Guide


         sign.  The metasymbols are:

             $*   Match zero or more tokens
             $+   Match one or more tokens
             $-   Match exactly one token
             $=x  Match any phrase in class x
             $~x  Match any word not in class x

         If  any  of  these  match, they are assigned to the
         symbol $n for replacement on the right  hand  side,
         where  n  is the index in the LHS.  For example, if
         the LHS:

             $-:$+

         is applied to the input:

             UCBARPA:eric

         the rule will match, and the values passed  to  the
         RHS will be:

             $1  UCBARPA
             $2  eric


              Additionally,  the LHS can include $@ to match
         zero tokens.  This is not bound to a $n on the RHS,
         and  is  normally only used when it stands alone in
         order to match the null input.

      5.1.2.  The right hand side

              When the left hand side of  a  rewriting  rule
         matches,  the  input is deleted and replaced by the
         right hand side.  Tokens are copied  directly  from
         the  RHS  unless  they  begin  with  a dollar sign.
         Metasymbols are:

             $n         Substitute indefinite token n from LHS
             $[name$]   Canonicalize name
             $(map key $@arguments $:default $)
                        Generalized keyed mapping function
             $>n        "Call" ruleset n
             $#mailer   Resolve to mailer
             $@host     Specify host
             $:user     Specify user


              The $n syntax  substitutes  the  corresponding
         value  from  a  $+,  $-, $*, $=, or $~ match on the
         LHS.  It may be used anywhere.











Sendmail Installation and Operation Guide          SMM:08-59


              A host name enclosed  between  $[  and  $]  is
         looked  up  in the host database(s) and replaced by
         the  canonical  name[14].   For  example, "$[ftp$]"
         might     become     "ftp.CS.Berkeley.EDU"      and
         "$[[128.32.130.2]$]"     would     become     "van-
         gogh.CS.Berkeley.EDU."   Sendmail  recognizes   its
         numeric  IP address without calling the name server
         and replaces it with its canonical name.

              The $( ...  $) syntax is a more  general  form
         of  lookup;  it  uses  a  named  map  instead of an
         implicit map.  If no lookup is found, the indicated
         default is inserted; if no default is specified and
         no lookup matches, the  value  is  left  unchanged.
         The  arguments  are  passed to the map for possible
         use.

              The $>n syntax causes  the  remainder  of  the
         line  to be substituted as usual and then passed as
         the argument to ruleset  n.   The  final  value  of
         ruleset  n  then  becomes the substitution for this
         rule.  The $> syntax expands everything  after  the
         ruleset  name  to the end of the replacement string
         and then passes that as the initial  input  to  the
         ruleset.   Recursive  calls are allowed.  For exam-
         ple,

             $>0 $>3 $1

         expands $1, passes that  to  ruleset  3,  and  then
         passes the result of ruleset 3 to ruleset 0.

              The  $#  syntax should only be used in ruleset
         zero, a subroutine of  ruleset  zero,  or  rulesets
         that   return  decisions  (e.g.,  check_rcpt).   It
         causes evaluation of the ruleset to terminate imme-
         diately,  and  signals to sendmail that the address
         has completely resolved.  The complete  syntax  for
         ruleset 0 is:

             $#mailer $@host $:user

         This  specifies  the  {mailer,  host, user} 3-tuple
         necessary to direct the mailer.  If the  mailer  is
         local the host part may be omitted[15].  The mailer
____________________
   [14]This is  actually  completely  equivalent  to  $(host
hostname$).  In particular, a $: default can be used.
   [15]You  may want to use it for special "per user" exten-
sions.  For example, in the address  "jgm+foo@CMU.EDU";  the
"+foo"  part  is not part of the user name, and is passed to
the local mailer for local use.











SMM:08-60          Sendmail Installation and Operation Guide


         must be a single word, but the host and user may be
         multi-part.  If the  mailer  is  the  built-in  IPC
         mailer,  the  host may be a colon-separated list of
         hosts that are searched  in  order  for  the  first
         working  address  (exactly  like  MX records).  The
         user is  later  rewritten  by  the  mailer-specific
         envelope  rewriting  set  and  assigned  to  the $u
         macro.  As a special case, if the mailer  specified
         has  the F=@ flag specified and the first character
         of the $: value is "@", the "@"  is  stripped  off,
         and  a  flag  is set in the address descriptor that
         causes sendmail to not do ruleset 5 processing.

              Normally, a rule that matches is retried, that
         is,  the rule loops until it fails.  A RHS may also
         be preceded by a $@ or a $: to change  this  behav-
         ior.  A $@ prefix causes the ruleset to return with
         the remainder of the RHS as the value.  A $: prefix
         causes  the  rule to terminate immediately, but the
         ruleset to continue; this can be used to avoid con-
         tinued  application  of  a  rule.   The  prefix  is
         stripped before continuing.

              The $@ and $: prefixes may precede a $>  spec;
         for example:

             R$+     $: $>7 $1

         matches anything, passes that to ruleset seven, and
         continues; the $: is necessary to avoid an infinite
         loop.

              Substitution  occurs  in  the order described,
         that is, parameters from the LHS  are  substituted,
         hostnames   are  canonicalized,  "subroutines"  are
         called, and finally $#, $@, and $: are processed.

      5.1.3.  Semantics of rewriting rule sets

              There are six rewriting sets  that  have  spe-
         cific  semantics.   Five  of  these  are related as
         depicted by figure 1.

              Ruleset three should  turn  the  address  into
         "canonical  form."  This form should have the basic
         syntax:

             local-part@host-domain-spec

         Ruleset three is applied by sendmail  before  doing
         anything with any address.












Sendmail Installation and Operation Guide          SMM:08-61



____________________________________________________________

                    +---+
                 -->| 0 |-->resolved address
                /   +---+
               /            +---+   +---+
              /        ---->| 1 |-->| S |--
       +---+ / +---+  /     +---+   +---+  \    +---+
addr-->| 3 |-->| D |--                      --->| 4 |-->msg
       +---+   +---+  \     +---+   +---+  /    +---+
                        --->| 2 |-->| R |--
                            +---+   +---+

            Figure 1 -- Rewriting set semantics
          D -- sender domain addition
          S -- mailer-specific sender rewriting
          R -- mailer-specific recipient rewriting
____________________________________________________________


              If  no  "@"  sign is specified, then the host-
         domain-spec may be appended (box "D" in  Figure  1)
         from  the  sender  address (if the C flag is set in
         the mailer definition corresponding to the  sending
         mailer).

              Ruleset zero is applied after ruleset three to
         addresses that are going to actually specify recip-
         ients.    It  must  resolve  to  a  {mailer,  host,
         address} triple.  The mailer must be defined in the
         mailer  definitions  from  the  configuration file.
         The host is defined into the $h macro  for  use  in
         the argv expansion of the specified mailer.

              Rulesets one and two are applied to all sender
         and recipient  addresses  respectively.   They  are
         applied before any specification in the mailer def-
         inition.  They must never resolve.

              Ruleset four is applied to  all  addresses  in
         the  message.   It  is  typically used to translate
         internal to external form.

              In addition, ruleset 5 is applied to all local
         addresses  (specifically,  those  that resolve to a
         mailer with the `F=5' flag set) that  do  not  have
         aliases.   This allows a last minute hook for local
         names.














SMM:08-62          Sendmail Installation and Operation Guide


      5.1.4.  Ruleset hooks

              A few extra rulesets are  defined  as  "hooks"
         that  can be defined to get special features.  They
         are all named rulesets.  The  "check_*"  forms  all
         give  accept/reject  status; falling off the end or
         returning normally is an accept, and  resolving  to
         $#error  is  a  reject.   Many  of  these  can also
         resolve to the special mailer name $#discard;  this
         accepts  the  message  as though it were successful
         but then discards it without delivery.  Note,  this
         mailer  cannot  be chosen as a mailer in ruleset 0.
         Note also that all "check_*" rulesets have to  deal
         with   temporary   failures,   especially  for  map
         lookups, themselves, i.e.,  they  should  return  a
         temporary error code or at least they should make a
         proper decision in those cases.

         5.1.4.1.  check_relay

                 The check_relay ruleset is called  after  a
            connection is accepted by the daemon.  It is not
            called when sendmail is started  using  the  -bs
            option.  It is passed

                client.host.name $| client.host.address

            where  $|  is a metacharacter separating the two
            parts.  This ruleset can reject connections from
            various locations.  Note that it only checks the
            connecting SMTP client IP address and  hostname.
            It does not check for third party message relay-
            ing.  The  check_rcpt  ruleset  discussed  below
            usually does third party message relay checking.

         5.1.4.2.  check_mail

                 The check_mail ruleset is passed  the  user
            name parameter of the SMTP MAIL command.  It can
            accept or reject the address.

         5.1.4.3.  check_rcpt

                 The check_rcpt ruleset is passed  the  user
            name parameter of the SMTP RCPT command.  It can
            accept or reject the address.

         5.1.4.4.  check_data

                 The check_data ruleset is called after  the
            SMTP  DATA  command, its parameter is the number
            of recipients.  It can accept or reject the com-
            mand.










Sendmail Installation and Operation Guide          SMM:08-63


         5.1.4.5.  check_compat

                 The check_compat ruleset is passed

                sender-address $| recipient-address

            where  $|  is  a  metacharacter  separating  the
            addresses.  It can accept or reject mail  trans-
            fer  between  these  two addresses much like the
            checkcompat() function.

         5.1.4.6.  check_eoh

                 The check_eoh ruleset is passed

                number-of-headers $| size-of-headers

            where $| is a metacharacter separating the  num-
            bers.   These  numbers can be used for size com-
            parisons with the arith  map.   The  ruleset  is
            triggered  after  all  of  the headers have been
            read.  It can be used to  correlate  information
            gathered  from  those  headers  using  the macro
            storage map.  One possible use is to check for a
            missing header.  For example:

                Kstorage macro
                HMessage-Id: $>CheckMessageId

                SCheckMessageId
                # Record the presence of the header
                R$*            $: $(storage {MessageIdCheck} $@ OK $) $1
                R< $+ @ $+ >   $@ OK
                R$*            $#error $: 553 Header Error

                Scheck_eoh
                # Check the macro
                R$*            $: < $&{MessageIdCheck} >
                # Clear the macro for the next message
                R$*            $: $(storage {MessageIdCheck} $) $1
                # Has a Message-Id: header
                R< $+ >        $@ OK
                # Allow missing Message-Id: from local mail
                R$*            $: < $&{client_name} >
                R< >           $@ OK
                R< $=w >       $@ OK
                # Otherwise, reject the mail
                R$*            $#error $: 553 Header Error

            Keep  in  mind  the  Message-Id: header is not a
            required header and is  not  a  guaranteed  spam
            indicator.   This  ruleset  is  an  example  and
            should probably not be used in production.










SMM:08-64          Sendmail Installation and Operation Guide


         5.1.4.7.  check_etrn

                 The check_etrn ruleset is passed the param-
            eter of the SMTP ETRN command.  It can accept or
            reject the command.

         5.1.4.8.  check_expn

                 The check_expn ruleset is passed  the  user
            name parameter of the SMTP EXPN command.  It can
            accept or reject the address.

         5.1.4.9.  check_vrfy

                 The check_vrfy ruleset is passed  the  user
            name parameter of the SMTP VRFY command.  It can
            accept or reject the command.

         5.1.4.10.  trust_auth

                 The trust_auth ruleset is passed the  AUTH=
            parameter  of the SMTP MAIL command.  It is used
            to  determine  whether  this  value  should   be
            trusted.  In  order  to  make this decision, the
            ruleset may make use of  the  various  ${auth_*}
            macros.   If  the  ruleset  does  resolve to the
            "error"  mailer  the  AUTH=  parameter  is   not
            trusted  and  hence  not  passed  on to the next
            relay.

         5.1.4.11.  tls_client

                 The tls_client ruleset is called when send-
            mail  acts  as  server, after a STARTTLS command
            has  been  issued,  and  from  check_mail.   The
            parameter is the value of ${verify} and STARTTLS
            or MAIL,  respectively.   If  the  ruleset  does
            resolve  to  the "error" mailer, the appropriate
            error code is returned to the client.

         5.1.4.12.  tls_server

                 The tls_server ruleset is called when send-
            mail  acts  as  client  after a STARTTLS command
            (should) have been issued.  The parameter is the
            value of ${verify}.  If the ruleset does resolve
            to the "error" mailer, the connection is aborted
            (treated  as non-deliverable with a permanent or
            temporary error).














Sendmail Installation and Operation Guide          SMM:08-65


         5.1.4.13.  tls_rcpt

                 The tls_rcpt ruleset is  called  each  time
            before a RCPT TO command is sent.  The parameter
            is the current recipient.  If the  ruleset  does
            resolve  to the "error" mailer, the RCPT TO com-
            mand is suppressed (treated  as  non-deliverable
            with  a  permanent  or  temporary  error).  This
            ruleset allows to require encryption or  verifi-
            cation  of  the recipient's MTA even if the mail
            is somehow  redirected  to  another  host.   For
            example,  sending  mail  to luke@endmail.org may
            get redirected to a host  named  death.star  and
            hence  the  tls_server  ruleset won't apply.  By
            introducing  per  recipient  restrictions   such
            attacks  (e.g.,  via  DNS  spoofing) can be made
            impossible.  See cf/README how this ruleset  can
            be used.

         5.1.4.14.  srv_features

                 The srv_features ruleset is called with the
            connecting client's host name when a client con-
            nects  to  sendmail.  This ruleset should return
            $# followed by a list of options (single charac-
            ters  delimited  by white space).  If the return
            value starts with anything else it  is  silently
            ignored.   Generally  upper case characters turn
            off a feature while lower case  characters  turn
            it  on.  The option `S' causes the server not to
            offer STARTTLS.  This is useful to interact with
            MTAs/MUAs  that have broken STARTTLS implementa-
            tions by simply not offering it.  `V' turns  off
            the  request for a client certificate during the
            TLS handshake.  Option `A' and `P' suppress SMTP
            AUTH  and PIPELINING, respectively.  The ruleset
            may return `$#temp' to indicate that there is  a
            temporary  problem  determining the correct fea-
            tures, e.g., if a map is unavailable.   In  that
            case, the SMTP server issues a temporary failure
            and does not accept email.

         5.1.4.15.  try_tls

                 The try_tls ruleset is called when sendmail
            connects  to  another  MTA.  If the ruleset does
            resolve to the "error" mailer, sendmail does not
            try  STARTTLS  even  if  it is offered.  This is
            useful to interact with MTAs  that  have  broken
            STARTTLS implementations by simply not using it.













SMM:08-66          Sendmail Installation and Operation Guide


         5.1.4.16.  authinfo

                 The authinfo ruleset is called  when  send-
            mail  tries  to authenticate to another MTA.  It
            should return $# followed by a  list  of  tokens
            that  are  used  for  SMTP  AUTH.  If the return
            value starts with anything else it  is  silently
            ignored.   Each  token is a tagged string of the
            form: "TDstring" (including the quotes), where

                T        Tag which describes the item
                D        Delimiter: ':' simple text follows
                         '=' string is base64 encoded
                string   Value of the item

            Valid values for the tag are:

                U        user (authorization) id
                I        authentication id
                P        password
                R        realm
                M        list of mechanisms delimited by spaces

            If this ruleset is defined, the option  Default-
            AuthInfo  is  ignored  (even if the ruleset does
            not return a ``useful'' result).

         5.1.4.17.  queuegroup

                 The queuegroup ruleset is  used  to  map  a
            recipient  address  to  a queue group name.  The
            input for the ruleset is a recipient address  as
            specified by the SMTP RCPT command.  The ruleset
            should return $# followed by the name of a queue
            group.  If the return value starts with anything
            else it is silently ignored.   See  the  section
            about  Queue  Groups  and  Queue Directories for
            further information.

      5.1.5.  IPC mailers

              Some special processing occurs if the  ruleset
         zero  resolves  to an IPC mailer (that is, a mailer
         that has "[IPC]" listed as the Path in the  M  con-
         figuration  line.   The host name passed after "$@"
         has MX expansion performed if not delivering via  a
         named socket; this looks the name up in DNS to find
         alternate delivery sites.

              The host name can also be provided as a dotted
         quad  or  an  IPv6  address in square brackets; for
         example:











Sendmail Installation and Operation Guide          SMM:08-67


             [128.32.149.78]

         or

             [IPv6:2002:c0a8:51d2::23f4]

         This causes direct conversion of the numeric  value
         to an IP host address.

              The  host  name  passed  in after the "$@" may
         also be a colon-separated list of hosts.   Each  is
         separately MX expanded and the results are concate-
         nated to make (essentially) one long MX list.   The
         intent here is to create "fake" MX records that are
         not published in DNS for private internal networks.

              As  a final special case, the host name can be
         passed in as a text string in square brackets:

             [ucbvax.berkeley.edu]

         This form avoids the MX  mapping.   N.B.:  This  is
         intended  only for situations where you have a net-
         work firewall or other host that  will  do  special
         processing  for  all  your  mail,  so  that your MX
         record points to a gateway  machine;  this  machine
         could  then  do  direct delivery to machines within
         your local domain.  Use of  this  feature  directly
         violates  RFC  1123 section 5.3.5: it should not be
         used lightly.

   5.2.  D -- Define Macro

           Macros are named with a single character or  with
      a  word  in  {braces}.   The  names  ``x'' and ``{x}''
      denote the  same  macro  for  every  single  character
      ``x''.   Single  character  names may be selected from
      the entire ASCII set, but user-defined  macros  should
      be  selected  from the set of upper case letters only.
      Lower case letters and special symbols are used inter-
      nally.   Long names beginning with a lower case letter
      or a punctuation character are  reserved  for  use  by
      sendmail,  so  user-defined  long  macro  names should
      begin with an upper case letter.

           The syntax for macro definitions is:

          Dxval

      where x is the name of the macro (which may be a  sin-
      gle  character  or  a  word  in braces) and val is the
      value it should have.  There should be no spaces given
      that do not actually belong in the macro value.










SMM:08-68          Sendmail Installation and Operation Guide


           Macros  are  interpolated using the construct $x,
      where x is the name of the macro to  be  interpolated.
      This interpolation is done when the configuration file
      is read, except in M lines.  The special construct $&x
      can  be used in R lines to get deferred interpolation.

           Conditionals can be specified using the syntax:

          $?x text1 $| text2 $.

      This interpolates text1 if the macro  $x  is  set  and
      non-null, and text2 otherwise.  The "else" ($|) clause
      may be omitted.

           The following  macros  are  defined  and/or  used
      internally  by  sendmail for interpolation into argv's
      for mailers or for other contexts.  The ones marked  *
      are  information  passed  into  sendmail[16], the ones
      marked # are information passed both  in  and  out  of
      sendmail,  and  the  unmarked macros are passed out of
      sendmail but are not otherwise used internally.  These
      macros are:

      $a   The  origination date in RFC 822 format.  This is
           extracted from the Date: line.

      $b   The current date in RFC 822 format.

      $c   The hop count.  This is a count of the number  of
           Received:  lines plus the value of the -h command
           line flag.

      $d   The current date in UNIX (ctime) format.

      $e*  (Obsolete;   use    SmtpGreetingMessage    option
           instead.)   The  SMTP  entry  message.   This  is
           printed out when SMTP starts up.  The first  word
           must  be  the  $j  macro as specified by RFC 821.
           Defaults to "$j Sendmail $v ready at  $b".   Com-
           monly redefined to include the configuration ver-
           sion number, e.g., "$j Sendmail  $v/$Z  ready  at
           $b"

      $f   The envelope sender (from) address.

      $g   The  sender  address  relative  to the recipient.
           For  example,  if  $f  is  "foo",  $g   will   be
____________________
   [16]As  of  version 8.6, all of these macros have reason-
able defaults.  Previous versions required that they be  de-
fined.












Sendmail Installation and Operation Guide          SMM:08-69


           "host!foo",  "foo@host.domain",  or  whatever  is
           appropriate for the receiving mailer.

      $h   The recipient host.  This is  set  in  ruleset  0
           from the $@ field of a parsed address.

      $i   The queue id, e.g., "f344MXxp018717".

      $j#  The  "official"  domain name for this site.  This
           is fully qualified if the full qualification  can
           be  found.   It must be redefined to be the fully
           qualified domain name if your system is not  con-
           figured so that information can find it automati-
           cally.

      $k   The UUCP node name (from the uname system  call).

      $l*  (Obsolete; use UnixFromLine option instead.)  The
           format of the UNIX from line.   Unless  you  have
           changed  the  UNIX mailbox format, you should not
           change the default, which is "From $g $d".

      $m   The domain part of the gethostname return  value.
           Under  normal  circumstances, $j is equivalent to
           $w.$m.

      $n*  The name of  the  daemon  (for  error  messages).
           Defaults to "MAILER-DAEMON".

      $o*  (Obsolete:  use  OperatorChars  option  instead.)
           The set of "operators" in addresses.  A  list  of
           characters  which  will  be considered tokens and
           which will separate tokens  when  doing  parsing.
           For  example,  if  "@" were in the $o macro, then
           the input "a@b" would be scanned as three tokens:
           "a," "@," and "b."  Defaults to ".:@[]", which is
           the minimum set necessary to do RFC 822  parsing;
           a  richer  set  of operators is ".:%@!/[]", which
           adds support for  UUCP,  the  %-hack,  and  X.400
           addresses.

      $p   Sendmail's process id.

      $q*  Default  format  of sender address.  The $q macro
           specifies how an address should appear in a  mes-
           sage  when  it is defaulted.  Defaults to "<$g>".
           It is commonly redefined to be "$?x$x <$g>$|$g$."
           or "$g$?x ($x)$.", corresponding to the following
           two formats:

               Eric Allman <eric@CS.Berkeley.EDU>
               eric@CS.Berkeley.EDU (Eric Allman)











SMM:08-70          Sendmail Installation and Operation Guide


           Sendmail properly quotes names that have  special
           characters if the first form is used.

      $r   Protocol  used  to receive the message.  Set from
           the -p command line flag or by  the  SMTP  server
           code.

      $s   Sender's host name.  Set from the -p command line
           flag or by the SMTP server code.

      $t   A numeric representation of the current time.

      $u   The recipient user.

      $v   The version number of the sendmail binary.

      $w#  The hostname of this site.  This is the root name
           of this host (but see below for caveats).

      $x   The full name of the sender.

      $z   The home directory of the recipient.

      $_   The   validated   sender   address.    See   also
           ${client_resolve}.

      ${addr_type}
           The type of the address which is currently  being
           rewritten.  This macro contains up to three char-
           acters, the first is either `e' or `h' for  enve-
           lope/header  address,  the second is a space, and
           the third is either `s' or `r' for sender/recipi-
           ent  address.   Notice:  for  header addresses no
           distinction is currently made between sender  and
           recipient  addresses,  i.e.,  the  macro contains
           only `h'.

      ${alg_bits}
           The maximum keylength (in bits) of the  symmetric
           encryption  algorithm  used for a TLS connection.
           This may be less than  the  effective  keylength,
           which  is  stored in ${cipher_bits}, for ``export
           controlled'' algorithms.

      ${auth_authen}
           The client's authentication credentials as deter-
           mined by authentication (only set if successful).
           The format depends  on  the  mechanism  used,  it
           might  be  just `user', or `user@realm', or some-
           thing similar (SMTP AUTH only).

      ${auth_author}
           The  authorization  identity,  i.e.   the   AUTH=










Sendmail Installation and Operation Guide          SMM:08-71


           parameter of the SMTP MAIL command if supplied.

      ${auth_type}
           The  mechanism used for SMTP authentication (only
           set if successful).

      ${auth_ssf}
           The keylength (in bits) of the symmetric  encryp-
           tion  algorithm  used for the security layer of a
           SASL mechanism.

      ${bodytype}
           The message body  type  (7BIT  or  8BITMIME),  as
           determined from the envelope.

      ${cert_issuer}
           The  DN  (distinguished name) of the CA (certifi-
           cate authority) that signed  the  presented  cer-
           tificate (the cert issuer) (STARTTLS only).

      ${cert_md5}
           The MD5 hash of the presented certificate (START-
           TLS only).

      ${cert_subject}
           The DN of the presented certificate  (called  the
           cert subject) (STARTTLS only).

      ${cipher}
           The  cipher  suite used for the connection, e.g.,
           EDH-DSS-DES-CBC3-SHA,  EDH-RSA-DES-CBC-SHA,  DES-
           CBC-MD5, DES-CBC3-SHA (STARTTLS only).

      ${cipher_bits}
           The  effective keylength (in bits) of the symmet-
           ric encryption algorithm used for a  TLS  connec-
           tion.

      ${client_addr}
           The   IP   address  of  the  SMTP  client.   IPv6
           addresses are  tagged  with  "IPv6:"  before  the
           address.  Defined in the SMTP server only.

      ${client_name}
           The  host  name  of the SMTP client.  This may be
           the client's bracketed IP address in the  form  [
           nnn.nnn.nnn.nnn     ]     for    IPv4    and    [
           IPv6:nnnn:...:nnnn ] for IPv6 if the client's  IP
           address is not resolvable, or if it is resolvable
           but the  IP  address  of  the  resolved  hostname
           doesn't  match  the original IP address.  Defined
           in   the   SMTP   server    only.     See    also
           ${client_resolve}.










SMM:08-72          Sendmail Installation and Operation Guide


      ${client_port}
           The  port  number of the SMTP client.  Defined in
           the SMTP server only.

      ${client_resolve}
           Holds  the  result  of  the  resolve   call   for
           ${client_name}.  Possible values are:

               OK        resolved successfully
               FAIL      permanent lookup failure
               FORGED    forward lookup doesn't match reverse lookup
               TEMP      temporary lookup failure

           Defined  in  the SMTP server only.  sendmail per-
           forms a hostname lookup on the IP address of  the
           connecting client.  Next the IP addresses of that
           hostname are looked up.  If the client IP address
           does  not  appear in that list, then the hostname
           is maybe forged.  This is reflected as the  value
           FORGED for ${client_resolve} and it also shows up
           in $_ as "(may be forged)".

      ${cn_issuer}
           The CN (common name) of the CA  that  signed  the
           presented certificate (STARTTLS only).

      ${cn_subject}
           The CN (common name) of the presented certificate
           (STARTTLS only).

      ${currHeader}
           Header value as quoted string (possibly truncated
           to  MAXNAME).   This  macro  is only available in
           header check rulesets.

      ${daemon_addr}
           The IP address the daemon  is  listening  on  for
           connections.

      ${daemon_family}
           The  network  family  if  the daemon is accepting
           network  connections.   Possible  values  include
           "inet", "inet6", "iso", "ns", "x.25"

      ${daemon_flags}
           The flags for the daemon as specified by the Mod-
           ifier=  part  of  DaemonPortOptions  whereby  the
           flags  are  separated  from each other by spaces,
           and upper case flags are doubled.  That is, Modi-
           fier=Ea  will  be represented as "EE a" in ${dae-
           mon_flags}, which is  required  for  testing  the
           flags in rulesets.











Sendmail Installation and Operation Guide          SMM:08-73


      ${daemon_info}
           Some information about a daemon as a text string.
           For example, "SMTP+queueing@00:30:00".

      ${daemon_name}
           The name of  the  daemon  from  DaemonPortOptions
           Name=  suboption.   If this suboption is not set,
           "Daemon#", where # is the daemon number, is used.

      ${daemon_port}
           The  port  the daemon is accepting connection on.
           Unless DaemonPortOptions is set, this  will  most
           likely be "25".

      ${deliveryMode}
           The  current delivery mode sendmail is using.  It
           is initially set to the value of the DeliveryMode
           option.

      ${envid}
           The  envelope  id  parameter  (ENVID=)  passed to
           sendmail as part of the envelope.

      ${hdrlen}
           The length of the header value which is stored in
           ${currHeader}  (before  possible truncation).  If
           this value is greater than or  equal  to  MAXNAME
           the header has been truncated.

      ${hdr_name}
           The  name  of the header field for which the cur-
           rent header check ruleset has been called.   This
           is  useful  for a default header check ruleset to
           get the name of the header;  the  macro  is  only
           available in header check rulesets.

      ${if_addr}
           The  IP  address  of the interface of an incoming
           connection unless it  is  in  the  loopback  net.
           IPv6 addresses are tagged with "IPv6:" before the
           address.

      ${if_addr_out}
           The IP address of the interface  of  an  outgoing
           connection  unless  it  is  in  the loopback net.
           IPv6 addresses are tagged with "IPv6:" before the
           address.

      ${if_family}
           The  IP  family  of  the interface of an incoming
           connection unless it is in the loopback net.












SMM:08-74          Sendmail Installation and Operation Guide


      ${if_family_out}
           The IP family of the  interface  of  an  outgoing
           connection unless it is in the loopback net.

      ${if_name}
           The  hostname associated with the interface of an
           incoming connection.  This macro can be used  for
           SmtpGreetingMessage  and  HReceived  for  virtual
           hosting.  For example:

               O SmtpGreetingMessage=$?{if_name}${if_name}$|$j$. MTA


      ${if_name_out}
           The name of the interface of an outgoing  connec-
           tion.

      ${load_avg}
           The current load average.

      ${mail_addr}
           The  address  part  of the resolved triple of the
           address given for the SMTP MAIL command.  Defined
           in the SMTP server only.

      ${mail_host}
           The  host from the resolved triple of the address
           given for the SMTP MAIL command.  Defined in  the
           SMTP server only.

      ${mail_mailer}
           The  mailer  from  the  resolved  triple  of  the
           address given for the SMTP MAIL command.  Defined
           in the SMTP server only.

      ${msg_size}
           The  value  of the SIZE= parameter, i.e., usually
           the size of the message (in an  ESMTP  dialogue),
           before the message has been collected, thereafter
           the message size as computed by sendmail (and can
           be used in check_compat).

      ${nrcpts}
           The  number  of validated recipients for a single
           message.  Note: since recipient  validation  hap-
           pens  after check_rcpt has been called, the value
           in this ruleset is one less than  what  might  be
           expected.

      ${ntries}
           The number of delivery attempts.












Sendmail Installation and Operation Guide          SMM:08-75


      ${opMode}
           The current operation mode (from the -b flag).

      ${queue_interval}
           The queue run interval given by the -q flag.  For
           example, -q30m  would  set  ${queue_interval}  to
           "00:30:00".

      ${rcpt_addr}
           The  address  part  of the resolved triple of the
           address given for the SMTP RCPT command.  Defined
           in the SMTP server only after a RCPT command.

      ${rcpt_host}
           The  host from the resolved triple of the address
           given for the SMTP RCPT command.  Defined in  the
           SMTP server only after a RCPT command.

      ${rcpt_mailer}
           The  mailer  from  the  resolved  triple  of  the
           address given for the SMTP RCPT command.  Defined
           in the SMTP server only after a RCPT command.

      ${server_addr}
           The address of the server of the current outgoing
           SMTP connection.  For LMTP delivery the macro  is
           set to the name of the mailer.

      ${server_name}
           The  name  of  the server of the current outgoing
           SMTP or LMTP connection.

      ${tls_version}
           The TLS/SSL  version  used  for  the  connection,
           e.g., TLSv1, SSLv3, SSLv2; defined after STARTTLS
           has been used.

      ${verify}
           The result of the verification of  the  presented
           cert;  only defined after STARTTLS has been used.
           Possible values are:

               OK           verification succeeded.
               NO           no cert presented.
               NOT          no cert requested.
               FAIL         cert presented but could not be verified,
                            e.g., the signing CA is missing.
               NONE         STARTTLS has not been performed.
               TEMP         temporary error occurred.
               PROTOCOL     some protocol error occurred.
               SOFTWARE     STARTTLS handshake failed,
                            which is a fatal error for this session,
                            the e-mail will be queued.










SMM:08-76          Sendmail Installation and Operation Guide


           There are three types of dates that can be  used.
      The  $a and $b macros are in RFC 822 format; $a is the
      time as extracted from the "Date:" line of the message
      (if  there  was  one),  and $b is the current date and
      time (used for postmarks).   If  no  "Date:"  line  is
      found  in  the incoming message, $a is set to the cur-
      rent time also.  The $d macro is equivalent to the  $b
      macro in UNIX (ctime) format.

           The macros $w, $j, and $m are set to the identity
      of this host.  Sendmail tries to find the fully quali-
      fied name of the host if at all possible; it does this
      by calling gethostname(2) to get the current  hostname
      and  then  passing  that  to gethostbyname(3) which is
      supposed to return the canonical version of that  host
      name.[17]  Assuming  this  is successful, $j is set to
      the fully qualified name and $m is set to  the  domain
      part  of  the  name  (everything after the first dot).
      The $w macro is set  to  the  first  word  (everything
      before  the first dot) if you have a level 5 or higher
      configuration file; otherwise, it is set to  the  same
      value as $j.  If the canonification is not successful,
      it is imperative that the config file set  $j  to  the
      fully qualified domain name[18].

           The  $f  macro  is the id of the sender as origi-
      nally determined; when mailing to a specific host  the
      $g  macro is set to the address of the sender relative
      to the recipient.  For example, if  I  send  to  "bol-
      lard@matisse.CS.Berkeley.EDU"  from  the machine "van-
      gogh.CS.Berkeley.EDU" the $f macro will be "eric"  and
      the $g macro will be "eric@vangogh.CS.Berkeley.EDU."

           The  $x  macro  is  set  to  the full name of the
      sender.  This can be determined in several  ways.   It
      can  be passed as flag to sendmail.  It can be defined
      in the NAME environment variable.  The third choice is
      the value of the "Full-Name:" line in the header if it
      exists, and the fourth choice is the comment field  of
      a "From:" line.  If all of these fail, and if the mes-
      sage is being originated locally,  the  full  name  is
      looked up in the /etc/passwd file.

           When  sending,  the $h, $u, and $z macros get set
      to the host, user, and home directory  (if  local)  of
____________________
   [17]For example, on some systems gethostname might return
"foo" which would be mapped to "foo.bar.com"  by  gethostby-
name.
   [18]Older  versions  of  sendmail didn't pre-define $j at
all, so up until 8.6, config files always had to define  $j.












Sendmail Installation and Operation Guide          SMM:08-77


      the  recipient.  The first two are set from the $@ and
      $: part of the rewriting rules, respectively.

           The $p and $t macros are used  to  create  unique
      strings  (e.g.,  for the "Message-Id:" field).  The $i
      macro is set to the queue id on this host; if put into
      the  timestamp  line  it  can  be extremely useful for
      tracking messages.  The $v macro is set to be the ver-
      sion number of sendmail; this is normally put in time-
      stamps and has been proven extremely useful for debug-
      ging.

           The $c field is set to the "hop count," i.e., the
      number of times this message has been processed.  This
      can  be  determined by the -h flag on the command line
      or by counting the timestamps in the message.

           The $r and $s fields are set to the protocol used
      to communicate with sendmail and the sending hostname.
      They can be set together using  the  -p  command  line
      flag or separately using the -M or -oM flags.

           The  $_  is  set to a validated sender host name.
      If the sender is running an RFC 1413  compliant  IDENT
      server  and the receiver has the IDENT protocol turned
      on, it will include the user name on that host.

           The    ${client_name},    ${client_addr},     and
      ${client_port}  macros  are  set to the name, address,
      and port number of the SMTP  client  who  is  invoking
      sendmail  as  a  server.   These  can  be  used in the
      check_* rulesets (using  the  $&  deferred  evaluation
      form, of course!).

   5.3.  C and F -- Define Classes

           Classes of phrases may be defined to match on the
      left hand side of rewriting rules, where a "phrase" is
      a  sequence  of characters that does not contain space
      characters.  For example a class of  all  local  names
      for  this  site  might  be created so that attempts to
      send to oneself can be eliminated.  These  can  either
      be  defined directly in the configuration file or read
      in from another file.  Classes are named as  a  single
      letter  or  a word in {braces}.  Class names beginning
      with lower case letters  and  special  characters  are
      reserved  for  system  use.  Classes defined in config
      files may be given names from the set  of  upper  case
      letters  for  short  names  or beginning with an upper
      case letter for long names.

           The syntax is:











SMM:08-78          Sendmail Installation and Operation Guide


          Ccphrase1 phrase2...
          Fcfile
          Fc|program
          Fc[mapkey]@mapclass:mapspec

      The first form defines the class c to match any of the
      named  words.  If phrase1 or phrase2 is another class,
      e.g., $=S, the contents of class S are added to  class
      c.   It  is  permissible  to split them among multiple
      lines; for example, the two forms:

          CHmonet ucbmonet

      and

          CHmonet
          CHucbmonet

      are equivalent.  The ``F'' forms read the elements  of
      the class c from the named file, program, or map spec-
      ification.  Each element should be listed on  a  sepa-
      rate  line.   To  specify an optional file, use ``-o''
      between the class name and the file name, e.g.,

          Fc -o /path/to/file

      If the file can't be used, sendmail will not  complain
      but  silently  ignore  it.   The map form should be an
      optional map key, an at sign, and a map class followed
      by the specification for that map.  Examples include:

          F{VirtHosts}@ldap:-k (&(objectClass=virtHosts)(host=*)) -v host
          F{MyClass}foo@hash:/etc/mail/classes

      will  fill  the  class  $={VirtHosts} from an LDAP map
      lookup and $={MyClass} from a hash database map lookup
      of  the foo.  There is also a built-in schema that can
      be accessed by only specifying:

          F{ClassName}@LDAP

      This will tell sendmail to use the default schema:

          -k (&(objectClass=sendmailMTAClass)
               (sendmailMTAClassName=ClassName)
               (|(sendmailMTACluster=${sendmailMTACluster})
                 (sendmailMTAHost=$j)))
          -v sendmailMTAClassValue

      Note that the lookup is only  done  when  sendmail  is
      initially started.












Sendmail Installation and Operation Guide          SMM:08-79


           Elements  of  classes  can  be  accessed in rules
      using $= or $~.  The $~ (match entries not  in  class)
      only  matches a single word; multi-word entries in the
      class are ignored in this context.

           Some classes have internal meaning to sendmail:

      $=e  contains the Content-Transfer-Encodings that  can
           be 8->7 bit encoded.  It is predefined to contain
           "7bit", "8bit", and "binary".

      $=k  set to be the same as $k, that is, the UUCP  node
           name.

      $=m  set  to  the set of domains by which this host is
           known, initially just $m.

      $=n  can be set to the set of MIME body types that can
           never be eight to seven bit encoded.  It defaults
           to "multipart/signed".  Message types "message/*"
           and  "multipart/*"  are  never  encoded directly.
           Multipart  messages  are  always  handled  recur-
           sively.   The  handling of message/* messages are
           controlled by class $=s.

      $=q  A set of Content-Types that will never be encoded
           as  base64 (if they have to be encoded, they will
           be encoded as  quoted-printable).   It  can  have
           primary  types (e.g., "text") or full types (such
           as "text/plain").  The class  is  initialized  to
           have "text/plain" only.

      $=s  contains  the set of subtypes of message that can
           be treated recursively.  By default  it  contains
           only "rfc822".  Other "message/*" types cannot be
           8->7 bit encoded.  If a message containing  eight
           bit  data  is  sent to a seven bit host, and that
           message cannot be encoded  into  seven  bits,  it
           will be stripped to 7 bits.

      $=t  set to the set of trusted users by the T configu-
           ration line.  If you want to read  trusted  users
           from a file, use Ft/file/name.

      $=w  set to be the set of all names this host is known
           by.  This can be used to match local hostnames.

      $={persistentMacros}
           set to the macros would should  be  saved  across
           queue  runs.   Care  should  be taken when adding
           macro names to this class.












SMM:08-80          Sendmail Installation and Operation Guide


           Sendmail can be  compiled  to  allow  a  scanf(3)
      string  on  the  F  line.  This lets you do simplistic
      parsing of text files.  For example, to read  all  the
      user  names  in  your  system  /etc/passwd file into a
      class, use

          FL/etc/passwd %[^:]

      which reads every line up to the first colon.

   5.4.  M -- Define Mailer

           Programs and interfaces to mailers are defined in
      this line.  The format is:

          Mname, {field=value}*

      where  name is the name of the mailer (used internally
      only) and the "field=name" pairs define attributes  of
      the mailer.  Fields are:

          Path      The pathname of the mailer
          Flags     Special flags for this mailer
          Sender    Rewriting set(s) for sender addresses
          Recipient Rewriting set(s) for recipient addresses
          recipientsMaximum number of recipients per connection
          Argv      An argument vector to pass to this mailer
          Eol       The end-of-line string for this mailer
          Maxsize   The maximum message length to this mailer
          maxmessagesThe maximum message deliveries per connection
          Linelimit The maximum line length in the message body
          Directory The working directory for the mailer
          Userid    The default user and group id to run as
          Nice      The nice(2) increment for the mailer
          Charset   The default character set for 8-bit characters
          Type      Type information for DSN diagnostics
          Wait      The maximum time to wait for the mailer
          QueuegroupThe default queue group for the mailer
          /         The root directory for the mailer

      Only  the first character of the field name is checked
      (it's case-sensitive).

           The following flags may  be  set  in  the  mailer
      description.   Any  other  flags may be used freely to
      conditionally assign headers to messages destined  for
      particular  mailers.   Flags  marked  with  *  are not
      interpreted by the sendmail binary; these are the con-
      ventionally  used to correlate to the flags portion of
      the H line.  Flags marked with # apply to the  mailers
      for the sender address rather than the usual recipient
      mailers.











Sendmail Installation and Operation Guide          SMM:08-81


      a   Run Extended SMTP  (ESMTP)  protocol  (defined  in
          RFCs 1869, 1652, and 1870).  This flag defaults on
          if the SMTP greeting  message  includes  the  word
          "ESMTP".

      A   Look  up the user part of the address in the alias
          database.  Normally this is  only  set  for  local
          mailers.

      b   Force  a blank line on the end of a message.  This
          is intended to work around some stupid versions of
          /bin/mail  that  require  a blank line, but do not
          provide it themselves.  It would not  normally  be
          used on network mail.

      c   Do not include comments in addresses.  This should
          only be used if you have to work around  a  remote
          mailer  that  gets  confused  by  comments.   This
          strips addresses of the form "Phrase <address>" or
          "address (Comment)" down to just "address".

      C#  If  mail  is received from a mailer with this flag
          set, any addresses in the header that do not  have
          an  at sign ("@") after being rewritten by ruleset
          three will have  the  "@domain"  clause  from  the
          sender  envelope  address  tacked on.  This allows
          mail with headers of the form:

              From: usera@hosta
              To: userb@hostb, userc

          to be rewritten as:

              From: usera@hosta
              To: userb@hostb, userc@hosta

          automatically.  However, it  doesn't  really  work
          reliably.

      d   Do not include angle brackets around route-address
          syntax addresses.  This is useful on mailers  that
          are  going to pass addresses to a shell that might
          interpret angle brackets as I/O redirection.  How-
          ever,  it  does  not  protect  against other shell
          metacharacters.  Therefore, passing addresses to a
          shell should not be considered secure.

      D*  This mailer wants a "Date:" header line.

      e   This  mailer is expensive to connect to, so try to
          avoid connecting normally; any  necessary  connec-
          tion  will  occur  during  a  queue run.  See also
          option HoldExpensive.










SMM:08-82          Sendmail Installation and Operation Guide


      E   Escape lines beginning with "From " in the message
          with a `>' sign.

      f   The  mailer wants a -f from flag, but only if this
          is a network forward operation (i.e.,  the  mailer
          will  give an error if the executing user does not
          have special permissions).

      F*  This mailer wants a "From:" header line.

      g   Normally,  sendmail  sends  internally   generated
          email (e.g., error messages) using the null return
          address as required by RFC  1123.   However,  some
          mailers  don't  accept  a null return address.  If
          necessary, you can set the g flag to prevent send-
          mail  from  obeying  the standards; error messages
          will be sent as from the MAILER-DAEMON  (actually,
          the value of the $n macro).

      h   Upper  case should be preserved in host names (the
          $@ portion of the  mailer  triplet  resolved  from
          ruleset 0) for this mailer.

      i   Do  User  Database  rewriting  on  envelope sender
          address.

      I   This mailer will be speaking SMTP to another send-
          mail  --  as such it can use special protocol fea-
          tures.  This flag should not be  used  except  for
          debugging  purposes  because  it uses VERB as SMTP
          command.

      j   Do User Database rewriting on recipients  as  well
          as senders.

      k   Normally  when  sendmail  connects  to  a host via
          SMTP, it checks to make sure that this isn't acci-
          dently the same host name as might happen if send-
          mail is misconfigured or if  a  long-haul  network
          interface is set in loopback mode.  This flag dis-
          ables the loopback check.  It should only be  used
          under very unusual circumstances.

      K   Currently unimplemented.  Reserved for chunking.

      l   This mailer is local (i.e., final delivery will be
          performed).

      L   Limit the line lengths as specified  in  RFC  821.
          This  deprecated  option should be replaced by the
          L= mail declaration.  For historic reasons, the  L
          flag also sets the 7 flag.











Sendmail Installation and Operation Guide          SMM:08-83


      m   This mailer can send to multiple users on the same
          host in one transaction.  When a $u  macro  occurs
          in  the  argv  part of the mailer definition, that
          field will be repeated as necessary for all quali-
          fying users.  Removing this flag can defeat dupli-
          cate supression on a remote site as each recipient
          is sent in a separate transaction.

      M*  This mailer wants a "Message-Id:" header line.

      n   Do  not  insert  a  UNIX-style  "From" line on the
          front of the message.

      o   Always run as the owner of the recipient  mailbox.
          Normally  sendmail  runs as the sender for locally
          generated mail or as "daemon" (actually, the  user
          specified in the u option) when delivering network
          mail.  The normal behavior  is  required  by  most
          local  mailers,  which will not allow the envelope
          sender address to be set unless the mailer is run-
          ning  as  daemon.   This  flag is ignored if the S
          flag is set.

      p   Use the route-addr style reverse-path in the  SMTP
          "MAIL  FROM:"  command rather than just the return
          address; although this is required in RFC 821 sec-
          tion  3.1, many hosts do not process reverse-paths
          properly.  Reverse-paths are  officially  discour-
          aged by RFC 1123.

      P*  This mailer wants a "Return-Path:" line.

      q   When  an  address  that resolves to this mailer is
          verified  (SMTP  VRFY   command),   generate   250
          responses  instead  of  252  responses.  This will
          imply that the address is local.

      r   Same as f, but sends a -r flag.

      R   Open  SMTP  connections  from  a  "secure"   port.
          Secure  ports  aren't  (secure, that is) except on
          UNIX machines, so it is  unclear  that  this  adds
          anything.   sendmail must be running as root to be
          able to use this flag.

      s   Strip quote  characters  ("  and  \)  off  of  the
          address before calling the mailer.

      S   Don't  reset the userid before calling the mailer.
          This would be used in a secure  environment  where
          sendmail ran as root.  This could be used to avoid
          forged addresses.  If the U= field is also  speci-
          fied, this flag causes the effective user id to be










SMM:08-84          Sendmail Installation and Operation Guide


          set to that user.

      u   Upper case should be preserved in user  names  for
          this  mailer.   Standards  require preservation of
          case in the local part of  addresses,  except  for
          those   address  for  which  your  system  accepts
          responsibility.  RFC 2142 provides a long list  of
          addresses  which  should  be case insensitive.  If
          you use this flag, you may be violating RFC  2142.
          Note  that  postmaster is always treated as a case
          insensitive address regardless of this flag.

      U   This mailer wants UUCP-style "From" lines with the
          ugly "remote from <host>" on the end.

      w   The  user  must  have  a  valid  account  on  this
          machine, i.e., getpwnam must succeed.  If not, the
          mail  is  bounced.   See  also the MailBoxDatabase
          option.  This is required to get ".forward"  capa-
          bility.

      x*  This mailer wants a "Full-Name:" header line.

      X   This  mailer wants to use the hidden dot algorithm
          as specified  in  RFC  821;  basically,  any  line
          beginning  with  a  dot  will  have  an  extra dot
          prepended (to be stripped at the other end).  This
          insures that lines in the message containing a dot
          will not terminate the message prematurely.

      z   Run Local Mail Transfer  Protocol  (LMTP)  between
          sendmail  and the local mailer.  This is a variant
          on SMTP defined in RFC 2033 that  is  specifically
          designed for delivery to a local mailbox.

      Z   Apply DialDelay (if set) to this mailer.

      0   Don't  look  up  MX  records  for  hosts  sent via
          SMTP/LMTP.  Do not apply FallbackMXhost either.

      1   Don't send null characters ('\0') to this  mailer.

      2   Don't  use  ESMTP  even if offered; this is useful
          for broken systems that offer ESMTP  but  fail  on
          EHLO (without recovering when HELO is tried next).

      3   Extend the list of  characters  converted  to  =XX
          notation  when  converting  to Quoted-Printable to
          include those that don't map cleanly between ASCII
          and  EBCDIC.  Useful if you have IBM mainframes on
          site.












Sendmail Installation and Operation Guide          SMM:08-85


      5   If no aliases are found for this address, pass the
          address  through  ruleset 5 for possible alternate
          resolution.  This is intended to forward the  mail
          to an alternate delivery spot.

      6   Strip headers to seven bits.

      7   Strip  all  output  to  seven  bits.   This is the
          default if the L flag is set.  Note that  clearing
          this  option  is  not sufficient to get full eight
          bit data passed through sendmail.  If the 7 option
          is  set, this is essentially always set, since the
          eighth bit was stripped on input.  Note that  this
          option  will only impact messages that didn't have
          8->7 bit MIME conversions performed.

      8   If set, it is acceptable to send eight bit data to
          this mailer; the usual attempt to do 8->7 bit MIME
          conversions will be bypassed.

      9   If set, do  limited  7->8  bit  MIME  conversions.
          These  conversions are limited to text/plain data.

      :   Check addresses to see if they begin  ":include:";
          if  they  do,  convert  them  to  the  "*include*"
          mailer.

      |   Check addresses to see if they begin with  a  `|';
          if they do, convert them to the "prog" mailer.

      /   Check  addresses  to see if they begin with a `/';
          if they do, convert them to the "*file*" mailer.

      @   Look up addresses in the user database.

      %   Do not attempt delivery on initial recipient of  a
          message or on queue runs unless the queued message
          is selected using one of the -qI/-qR/-qS queue run
          modifiers or an ETRN request.

           Configuration  files  prior to level 6 assume the
      `A', `w', `5', `:', `|', `/', and `@' options  on  the
      mailer named "local".

           The  mailer  with the special name "error" can be
      used to generate a user error.   The  (optional)  host
      field  is  an exit status to be returned, and the user
      field is a message to be printed.  The exit status may
      be numeric or one of the values USAGE, NOUSER, NOHOST,
      UNAVAILABLE, SOFTWARE, TEMPFAIL, PROTOCOL,  or  CONFIG
      to  return  the  corresponding  EX_  exit  code, or an
      enhanced error code as described in RFC 1893, Enhanced
      Mail System Status Codes.  For example, the entry:










SMM:08-86          Sendmail Installation and Operation Guide


          $#error $@ NOHOST $: Host unknown in this domain

      on the RHS of a rule will cause the specified error to
      be generated and the "Host unknown" exit status to  be
      returned  if  the  LHS  matches.   This mailer is only
      functional in rulesets 0, 5, or  one  of  the  check_*
      rulesets.

           The mailer with the special name "discard" causes
      any mail sent to it  to  be  discarded  but  otherwise
      treated  as  though  it  were  successfully delivered.
      This mailer cannot be used in ruleset 0, only  in  the
      various address checking rulesets.

           The mailer named "local" must be defined in every
      configuration file.  This is  used  to  deliver  local
      mail, and is treated specially in several ways.  Addi-
      tionally, three other mailers named "prog",  "*file*",
      and "*include*" may be defined to tune the delivery of
      messages  to  programs,  files,  and  :include:  lists
      respectively.  They default to:

          Mprog, P=/bin/sh, F=lsoDq9, T=DNS/RFC822/X-Unix, A=sh -c $u
          M*file*, P=[FILE], F=lsDFMPEouq9, T=DNS/RFC822/X-Unix, A=FILE $u
          M*include*, P=/dev/null, F=su, A=INCLUDE $u


           Builtin  pathnames are [FILE] and [IPC], the for-
      mer is used for delivery  to  files,  the  latter  for
      delivery  via interprocess communication.  For mailers
      that use [IPC] as pathname the  argument  vector  (A=)
      must  start with TCP or FILE for delivery via a TCP or
      a Unix domain socket.  If  TCP  is  used,  the  second
      argument  must  be  the  name  of the host to contact.
      Optionally a third argument can be used to  specify  a
      port, the default is smtp (port 25).  If FILE is used,
      the second argument must  be  the  name  of  the  Unix
      domain socket.

           If  the  argument vector does not contain $u then
      sendmail will speak SMTP (or LMTP if the mailer flag z
      is specified) to the mailer.

           If  no  Eol field is defined, then the default is
      "\r\n" for SMTP mailers and "\n" of others.

           The  Sender  and  Recipient  rewriting  sets  may
      either  be a simple ruleset id or may be two ids sepa-
      rated by a slash; if so, the first  rewriting  set  is
      applied  to  envelope  addresses  and  the  second  is
      applied to headers.  Setting any value  to  zero  dis-
      ables corresponding mailer-specific rewriting.











Sendmail Installation and Operation Guide          SMM:08-87


           The  Directory is actually a colon-separated path
      of directories to try.  For  example,  the  definition
      "D=$z:/"  first  tries  to  execute in the recipient's
      home directory; if that is not available, it tries  to
      execute  in  the  root  of  the  filesystem.   This is
      intended to be used only on the "prog"  mailer,  since
      some  shells  (such  as csh) refuse to execute if they
      cannot read the current directory.   Since  the  queue
      directory  is  not  normally  readable by unprivileged
      users csh scripts as recipients can fail.

           The Userid specifies the default user  and  group
      id  to  run  as,  overriding  the  DefaultUser  option
      (q.v.).  If the S mailer flag is also specified,  this
      user  and  group  will be set as the effective uid and
      gid for the process.  This may be given as  user:group
      to  set  both  the user and group id; either may be an
      integer or a symbolic name to  be  looked  up  in  the
      passwd  and  group files respectively.  If only a sym-
      bolic user name is specified,  the  group  id  in  the
      passwd file for that user is used as the group id.

           The  Charset field is used when converting a mes-
      sage to MIME; this is the character set  used  in  the
      Content-Type:   header.   If  this  is  not  set,  the
      DefaultCharset option is used, and if that is not set,
      the value "unknown-8bit" is used.  WARNING: this field
      applies to the sender's mailer,  not  the  recipient's
      mailer.   For  example, if the envelope sender address
      lists an address on the local network and the  recipi-
      ent  is on an external network, the character set will
      be set from the Charset= field for the  local  network
      mailer, not that of the external network mailer.

           The Type= field sets the type information used in
      MIME error messages as defined by  RFC  1894.   It  is
      actually  three  values separated by slashes: the MTA-
      type (that  is,  the  description  of  how  hosts  are
      named),  the  address  type (the description of e-mail
      addresses), and the diagnostic type  (the  description
      of  error  diagnostic codes).  Each of these must be a
      registered value or begin with "X-".  The  default  is
      "dns/rfc822/smtp".

           The m= field specifies the maximum number of mes-
      sages to attempt to deliver on a single SMTP  or  LMTP
      connection.  The default is infinite.

           The  r=  field  specifies  the  maximum number of
      recipients to attempt to deliver in a single envelope.
      It defaults to 100.












SMM:08-88          Sendmail Installation and Operation Guide


           The  /=  field specifies a new root directory for
      the mailer.  The  path  is  macro  expanded  and  then
      passed  to  the "chroot" system call.  The root direc-
      tory is changed before the  Directory  field  is  con-
      sulted or the uid is changed.

           The  Wait=  field  specifies  the maximum time to
      wait for the mailer to return after sending  all  data
      to  it.  This applies to mailers that have been forked
      by sendmail.

           The Queuegroup= field specifies the default queue
      group  in  which received mail should be queued.  This
      can be overridden by other means as explained in  sec-
      tion ``Queue Groups and Queue Directories''.

   5.5.  H -- Define Header

           The  format  of  the  header  lines that sendmail
      inserts into the message are defined by  the  H  line.
      The syntax of this line is one of the following:

          Hhname: htemplate


          H[?mflags?]hname: htemplate


          H[?${macro}?]hname: htemplate

      Continuation lines in this spec are reflected directly
      into the outgoing message.  The  htemplate  is  macro-
      expanded  before  insertion  into the message.  If the
      mflags (surrounded by question marks)  are  specified,
      at  least one of the specified flags must be stated in
      the mailer definition for this header to be  automati-
      cally  output.   If a ${macro} (surrounded by question
      marks) is specified, the header will be  automatically
      output  if  the  macro  is  set.  The macro may be set
      using any of the normal methods, including  using  the
      macro storage map in a ruleset.  If one of these head-
      ers is in the input it  is  reflected  to  the  output
      regardless  of  these  flags  or macros.  Notice: If a
      ${macro} is used to set a header, then it is useful to
      add  that  macro  to  class $={persistentMacros} which
      consists of the macros that  should  be  saved  across
      queue runs.

           Some  headers have special semantics that will be
      described later.

           A secondary syntax allows validation  of  headers
      as they are being read.  To enable validation, use:










Sendmail Installation and Operation Guide          SMM:08-89


          HHeader: $>Ruleset
          HHeader: $>+Ruleset

      The  indicated  Ruleset  is  called  for the specified
      Header, and can return $#error to reject  the  message
      or $#discard to discard the message (as with the other
      check_* rulesets).  The ruleset  receives  the  header
      field-body  as  argument,  i.e., not the header field-
      name; see also  ${hdr_name}  and  ${currHeader}.   The
      header is treated as a structured field, that is, text
      in parentheses is deleted  before  processing,  unless
      the  second  form $>+ is used.  Note: only one ruleset
      can  be  associated  with  a  header;  sendmail   will
      silently ignore multiple entries.

           For example, the configuration lines:

          HMessage-Id: $>CheckMessageId

          SCheckMessageId
          R< $+ @ $+  >$@ OK
          R$*       $#error $: Illegal Message-Id header

      would refuse any message that had a Message-Id: header
      of any of the following forms:

          Message-Id: <>
          Message-Id: some text
          Message-Id: <legal text@domain> extra crud

      A default ruleset that is  called  for  headers  which
      don't  have a specific ruleset defined for them can be
      specified by:

          H*: $>Ruleset

      or

          H*: $>+Ruleset


   5.6.  O -- Set Option

           There are a number of global options that can  be
      set  from  a  configuration  file.  Options are repre-
      sented by full words; some are also  representable  as
      single  characters for back compatibility.  The syntax
      of this line is:

          O  option=value

      This sets option option to be value.  Note that  there
      must be a space between the letter `O' and the name of










SMM:08-90          Sendmail Installation and Operation Guide


      the option.  An older version is:

          Oovalue

      where the option o is a single  character.   Depending
      on  the  option,  value may be a string, an integer, a
      boolean (with legal values "t", "T", "f", or "F";  the
      default is TRUE), or a time interval.

           All  filenames used in options should be absolute
      paths, i.e., starting with  '/'.   Relative  filenames
      most  likely  cause surprises during operation (unless
      otherwise noted).

           The options supported (with the old, one  charac-
      ter names in brackets) are:

      AliasFile=spec, spec, ...
                [A]  Specify  possible  alias file(s).  Each
                spec should be in the format ``class: info''
                where  class:  is  optional  and defaults to
                ``implicit''.  Note that  info  is  required
                for  all  classes  except  "ldap".   For the
                "ldap" class, if info is  not  specified,  a
                default info value is used as follows:

                    -k (&(objectClass=sendmailMTAAliasObject)
                         (sendmailMTAAliasName=aliases)
                         (|(sendmailMTACluster=${sendmailMTACluster})
                           (sendmailMTAHost=$j))
                         (sendmailMTAKey=%0))
                    -v sendmailMTAAliasValue

                Depending on how sendmail is compiled, valid
                classes are  "implicit"  (search  through  a
                compiled-in  list  of  alias file types, for
                back compatibility),  "hash"  (if  NEWDB  is
                specified), "btree" (if NEWDB is specified),
                "dbm" (if NDBM is specified), "stab" (inter-
                nal symbol table -- not normally used unless
                you  have   no   other   database   lookup),
                "sequence"  (use  a  sequence of maps previ-
                ously declared), "ldap" (if LDAPMAP is spec-
                ified),  or "nis" (if NIS is specified).  If
                a  list  of  specs  are  provided,  sendmail
                searches them in order.

      AliasWait=timeout
                [a]  If  set,  wait  up  to  timeout  (units
                default to minutes) for an  "@:@"  entry  to
                exist  in the alias database before starting
                up.  If it does not appear  in  the  timeout
                interval issue a warning.










Sendmail Installation and Operation Guide          SMM:08-91


      AllowBogusHELO
                [no short name] If set, allow HELO SMTP com-
                mands that don't include a host name.   Set-
                ting  this  violates RFC 1123 section 5.2.5,
                but is necessary to interoperate  with  sev-
                eral  SMTP clients.  If there is a value, it
                is still checked for legitimacy.

      AuthMaxBits=N
                [no short name] Limit the maximum encryption
                strength for the security layer in SMTP AUTH
                (SASL). Default  is  essentially  unlimited.
                This  allows  to turn off additional encryp-
                tion in SASL if STARTTLS is already encrypt-
                ing  the communication, because the existing
                encryption strength is  taken  into  account
                when  choosing an algorithm for the security
                layer.  For example, if STARTTLS is used and
                the  symmetric  cipher is 3DES, then the the
                keylength (in bits) is 168.   Hence  setting
                AuthMaxBits  to 168 will disable any encryp-
                tion in SASL.

      AuthMechanisms
                [no short name] List of authentication mech-
                anisms  for AUTH (separated by spaces).  The
                advertised list of authentication mechanisms
                will  be  the  intersection of this list and
                the list of available mechanisms  as  deter-
                mined  by the Cyrus SASL library.  If START-
                TLS is active, EXTERNAL  will  be  added  to
                this  list.   In  that  case,  the  value of
                {cert_subject} is used as authentication id.

      AuthOptions
                [no  short  name]  List  of options for SMTP
                AUTH consisting of  single  characters  with
                intervening white space or commas.

























SMM:08-92          Sendmail Installation and Operation Guide


                    A   Use the AUTH= parameter for the MAIL FROM
                        command only when authentication succeeded.
                        This can be used as a workaround for broken
                        MTAs that do not implement RFC 2554 correctly.
                    a   protection from active (non-dictionary) attacks
                        during authentication exchange.
                    c   require mechanisms which pass client credentials,
                        and allow mechanisms which can pass credentials
                        to do so.
                    d   don't permit mechanisms susceptible to passive
                        dictionary attack.
                    f   require forward secrecy between sessions
                        (breaking one won't help break next).
                    p   don't permit mechanisms susceptible to simple
                        passive attack (e.g., PLAIN, LOGIN), unless a
                        security layer is active.
                    y   don't permit mechanisms that allow anonymous login.

                The  first  option  applies to sendmail as a
                client, the others to a server.  Example:

                    O AuthOptions=p,y

                would disallow ANONYMOUS as  AUTH  mechanism
                and  would  allow  PLAIN and LOGIN only if a
                security layer (e.g., provided by  STARTTLS)
                is  already  active.   The options 'a', 'c',
                'd', 'f', 'p', and 'y' refer  to  properties
                of  the  selected SASL mechanisms.  Explana-
                tions of these properties can  be  found  in
                the Cyrus SASL documentation.

      BadRcptThrottle=N
                [no  short  name]  If  set and the specified
                number of recipients in a single SMTP trans-
                action  have  been  rejected,  sleep for one
                second after each subsequent RCPT command in
                that transaction.

      BlankSub=c
                [B]  Set the blank substitution character to
                c.   Unquoted  spaces   in   addresses   are
                replaced  by  this  character.   Defaults to
                space (i.e., no change is made).

      CACertPath
                [no short name] Path to directory with  cer-
                tificates  of CAs.  This directory directory
                must contain the hashes of each CA  certifi-
                cate as filenames (or as links to them).

      CACertFile
                [no  short name] File containing one or more










Sendmail Installation and Operation Guide          SMM:08-93


                CA certificates; see section about  STARTTLS
                for more information.

      CheckAliases
                [n]   Validate   the  RHS  of  aliases  when
                rebuilding the alias database.

      CheckpointInterval=N
                [C] Checkpoints the queue every  N  (default
                10)  addresses sent.  If your system crashes
                during delivery to a large list,  this  pre-
                vents  retransmission  to any but the last N
                recipients.

      ClassFactor=fact
                [z] The indicated factor  is  multiplied  by
                the  message class (determined by the Prece-
                dence: field in the user header  and  the  P
                lines  in  the  configuration file) and sub-
                tracted from the priority.   Thus,  messages
                with  a  higher  Priority:  will be favored.
                Defaults to 1800.

      ClientCertFile
                [no short name] File containing the certifi-
                cate  of  the client, i.e., this certificate
                is used when sendmail acts  as  client  (for
                STARTTLS).

      ClientKeyFile
                [no  short name] File containing the private
                key belonging to the client certificate (for
                STARTTLS if sendmail runs as client).

      ClientPortOptions=options
                [O]  Set  client  SMTP options.  The options
                are key=value  pairs  separated  by  commas.
                Known keys are:

                    Port      Name/number of source port for connection (defaults to any free port)
                    Addr      Address mask (defaults INADDR_ANY)
                    Family    Address family (defaults to INET)
                    SndBufSizeSize of TCP send buffer
                    RcvBufSizeSize of TCP receive buffer
                    Modifier  Options (flags) for the client

                The Address mask may be a numeric address in
                dot notation or a  network  name.   Modifier
                can be the following character:

                    h         use name of interface for HELO command
                    A         don't use AUTH when sending e-mail
                    S         don't use STARTTLS when sending e-mail










SMM:08-94          Sendmail Installation and Operation Guide


                If  ``h''  is set, the name corresponding to
                the outgoing interface address (whether cho-
                sen  via  the  Connection  parameter  or the
                default) is used for the HELO/EHLO  command.
                However,  the  name  must  not  start with a
                square bracket and it must contain at  least
                one  dot.  This is a simple test whether the
                name is not an IP address (in square  brack-
                ets)  but  a  qualified hostname.  Note that
                multiple  ClientPortOptions   settings   are
                allowed  in  order to give settings for each
                protocol family (e.g., one  for  Family=inet
                and  one  for  Family=inet6).  A restriction
                placed on one family only  affects  outgoing
                connections on that particular family.

      ColonOkInAddr
                [no  short  name] If set, colons are accept-
                able    in    e-mail    addresses     (e.g.,
                "host:user").   If  not set, colons indicate
                the beginning of a RFC 822  group  construct
                ("groupname:   member1,  member2,  ...  mem-
                berN;").  Doubled colons are always  accept-
                able  ("nodename::user")  and  proper route-
                addr       nesting       is       understood
                ("<@relay:user@host>").   Furthermore,  this
                option defaults on if the configuration ver-
                sion level is less than 6 (for back compati-
                bility).  However, it must be off  for  full
                compatibility with RFC 822.

      ConnectionCacheSize=N
                [k]  The  maximum number of open connections
                that will be cached at a time.  The  default
                is  one.   This  delays  closing the current
                connection until either this  invocation  of
                sendmail needs to connect to another host or
                it terminates.  Setting it to zero  defaults
                to  the  old  behavior, that is, connections
                are closed immediately.  Since this consumes
                file   descriptors,   the  connection  cache
                should be kept small: 4 is probably a  prac-
                tical maximum.

      ConnectionCacheTimeout=timeout
                [K] The maximum amount of time a cached con-
                nection will be permitted  to  idle  without
                activity.   If  this  time  is exceeded, the
                connection  is  immediately  closed.    This
                value  should  be small (on the order of ten
                minutes).  Before  sendmail  uses  a  cached
                connection,  it  always sends a RSET command
                to check the connection; if this  fails,  it










Sendmail Installation and Operation Guide          SMM:08-95


                reopens the connection.  This keeps your end
                from failing if the  other  end  times  out.
                The  point  of  this  option is to be a good
                network neighbor and avoid using  up  exces-
                sive   resources  on  the  other  end.   The
                default is five minutes.

      ConnectOnlyTo=address
                [no short name] This can be used to override
                the  connection  address  (for  testing pur-
                poses).

      ConnectionRateThrottle=N
                [no short name] If set to a positive  value,
                allow no more than N incoming connections in
                a one second period  per  daemon.   This  is
                intended  to flatten out peaks and allow the
                load average checking to cut  in.   Defaults
                to zero (no limits).

      ControlSocketName=name
                [no  short  name] Name of the control socket
                for daemon management.  A  running  sendmail
                daemon  can be controlled through this named
                socket.   Available  commands   are:   help,
                restart,  shutdown,  and status.  The status
                command returns the current number of daemon
                children, the maximum number of daemon chil-
                dren, the free disk space (in blocks) of the
                queue directory, and the load average of the
                machine expressed as  an  integer.   If  not
                set,  no  control  socket will be available.
                Solaris and pre-4.4BSD kernel  users  should
                see the note in sendmail/README .

      DHParameters
                File  with DH parameters for STARTTLS.  This
                is only required if a ciphersuite containing
                DSA/DH  is  used.   This  is only for people
                with a good knowledge of TLS, all others can
                ignore this option.

      DaemonPortOptions=options
                [O]  Set server SMTP options.  Each instance
                of DaemonPortOptions leads to an  additional
                incoming  socket.  The options are key=value
                pairs.  Known keys are:
















SMM:08-96          Sendmail Installation and Operation Guide


                    Name      User-definable name for the daemon (defaults to "Daemon#")
                    Port      Name/number of listening port (defaults to "smtp")
                    Addr      Address mask (defaults INADDR_ANY)
                    Family    Address family (defaults to INET)
                    Listen    Size of listen queue (defaults to 10)
                    Modifier  Options (flags) for the daemon
                    SndBufSizeSize of TCP send buffer
                    RcvBufSizeSize of TCP receive buffer

                The Name key is used for error messages  and
                logging.   The Address mask may be a numeric
                address in dot notation or a  network  name.
                The  Family  key  defaults  to  INET (IPv4).
                IPv6 users who wish to also accept IPv6 con-
                nections  should add additional Family=inet6
                DaemonPortOptions lines.  Modifier can be  a
                sequence  (without  any  delimiters)  of the
                following characters:

                    a         always require authentication
                    b         bind to interface through which mail has been received
                    c         perform hostname canonification (.cf)
                    f         require fully qualified hostname (.cf)
                    u         allow unqualified addresses (.cf)
                    A         disable AUTH (overrides 'a' modifier)
                    C         don't perform hostname canonification
                    E         disallow ETRN (see RFC 2476)
                    O         optional; if opening the socket fails ignore it
                    S         don't offer STARTTLS

                That is, one way to specify a  message  sub-
                mission  agent  (MSA)  that  always requires
                authentication is:

                    O DaemonPortOptions=Name=MSA, Port=587, M=Ea

                The modifiers that are marked  with  "(.cf)"
                have  only effect in the standard configura-
                tion file, in which they are  available  via
                ${daemon_flags}.   Notice:  Do  not  use the
                ``a'' modifier on a public  accessible  MTA!
                It  should  only  be  used for a MSA that is
                accessed by  authorized  users  for  initial
                mail submission.  Users must authenticate to
                use a MSA which has this option  turned  on.
                The  flags  ``c''  and  ``C'' can change the
                default for hostname canonification  in  the
                sendmail.cf file.  See the relevant documen-
                tation for FEATURE(nocanonify).   The  modi-
                fier  ``f''  disallows addresses of the form
                user@host   unless   they   are    submitted
                directly.  The flag ``u'' allows unqualified
                sender addresses, i.e., those without @host.










Sendmail Installation and Operation Guide          SMM:08-97


                ``b''  forces sendmail to bind to the inter-
                face  through  which  the  e-mail  has  been
                received for the outgoing connection.  WARN-
                ING: Use ``b'' only if outgoing mail can  be
                routed  through  the  incoming  connection's
                interface to its destination. No attempt  is
                made  to catch problems due to a misconfigu-
                ration of this parameter, use  it  only  for
                virtual hosting where each virtual interface
                can  connect  to  every  possible  location.
                This  will  also  override possible settings
                via ClientPortOptions.  Note, sendmail  will
                listen on a new socket for each occurence of
                the DaemonPortOptions option in a configura-
                tion  file.  The modifier ``O'' causes send-
                mail to ignore  a  socket  if  it  can't  be
                opened.   This  applies to failures from the
                socket(2) and bind(2) calls.

      DefaultAuthInfo
                [no  short  name]  Filename  that   contains
                default  authentication information for out-
                going connections. This  file  must  contain
                the user id, the authorization id, the pass-
                word (plain text), the realm and the list of
                mechanisms to use on separate lines and must
                be readable by root (or  the  trusted  user)
                only.  If no realm is specified, $j is used.
                If no mechanisms  are  specified,  the  list
                given  by  AuthMechanisms  is used.  Notice:
                this  option  is  deprecated  and  will   be
                removed  in  future  versions.  Moreover, it
                doesn't work for the MSP since it can't read
                the  file (the file must not be group/world-
                readable otherwise sendmail will  complain).
                Use  the authinfo ruleset instead which pro-
                vides more control over  the  usage  of  the
                data anyway.

      DefaultCharSet=charset
                [no  short  name]  When  a  message that has
                8-bit characters but is not in  MIME  format
                is  converted  to MIME (see the EightBitMode
                option) a character set must be included  in
                the  Content-Type:  header.   This character
                set is normally set from the Charset=  field
                of  the  mailer  descriptor.  If that is not
                set, the value of this option is  used.   If
                this   option   is   not   set,   the  value
                "unknown-8bit" is used.

      DataFileBufferSize=threshold
                [no short name] Set the threshold, in bytes,










SMM:08-98          Sendmail Installation and Operation Guide


                before   a   memory-based  queue  data  file
                becomes disk-based.   The  default  is  4096
                bytes.

      DeadLetterDrop=file
                [no  short name] Defines the location of the
                system-wide dead.letter file, formerly hard-
                coded   to  /usr/tmp/dead.letter.   If  this
                option is not set  (the  default),  sendmail
                will  not  attempt  to save to a system-wide
                dead.letter file  in  the  event  it  cannot
                bounce  the  mail to the user or postmaster.
                Instead, it will rename the qf  file  as  it
                has  in  the  past when the dead.letter file
                could not be opened.

      DefaultUser=user:group
                [u] Set the default userid  for  mailers  to
                user:group.  If group is omitted and user is
                a user name (as opposed to  a  numeric  user
                id)   the   default   group  listed  in  the
                /etc/passwd file for that user  is  used  as
                the  default group.  Both user and group may
                be numeric.  Mailers without the S  flag  in
                the mailer definition will run as this user.
                Defaults to 1:1.   The  value  can  also  be
                given as a symbolic user name.[19]

      DelayLA=LA
                [no short name] When the system load average
                exceeds LA, sendmail will sleep for one sec-
                ond on most SMTP commands and before accept-
                ing connections.

      DeliverByMin=time
                [0]  Set  minimum  time  for Deliver By SMTP
                Service Extension (RFC 2852).  If 0, no time
                is  listed, if less than 0, the extension is
                not offered, if greater than 0, it is listed
                as  minimum time for the EHLO keyword DELIV-
                ERBY.

      DeliveryMode=x
                [d] Deliver in mode x.  Legal modes are:




____________________
   [19]The  old g option has been combined into the Default-
User option.












Sendmail Installation and Operation Guide          SMM:08-99


                    i   Deliver interactively (synchronously)
                    b   Deliver in background (asynchronously)
                    q   Just queue the message (deliver during queue run)
                    d   Defer delivery and all map lookups (deliver during queue run)

                Defaults to ``b'' if no option is specified,
                ``i''  if it is specified but given no argu-
                ment  (i.e.,   ``Od''   is   equivalent   to
                ``Odi'').   The  -v  command  line flag sets
                this to i.

      DialDelay=sleeptime
                [no short name] Dial-on-demand network  con-
                nections can see timeouts if a connection is
                opened before the call is set up.   If  this
                is set to an interval and a connection times
                out on the first connection being  attempted
                sendmail  will sleep for this amount of time
                and try again.  This should give your system
                time  to  establish  the  connection to your
                service provider.  Units default to seconds,
                so  "DialDelay=5"  uses a five second delay.
                Defaults to zero  (no  retry).   This  delay
                only  applies  to  mailers  which have the Z
                flag set.

      DirectSubmissionModifiers=modifiers
                Defines ${daemon_flags} for direct  (command
                line)   submissions.   If  not  set,  ${dae-
                mon_flags} is either "CC f" if the option -G
                is  used or "c u" otherwise.  Note that only
                the the "CC", "c", "f", and  "u"  flags  are
                checked.

      DontBlameSendmail=option,option,...
                [no  short  name] In order to avoid possible
                cracking  attempts  caused  by  world-   and
                group-writable  files and directories, send-
                mail does  paranoid  checking  when  opening
                most of its support files.  If for some rea-
                son you absolutely must run with, for  exam-
                ple,  a  group-writable /etc directory, then
                you will have to turn off this checking  (at
                the cost of making your system more vulnera-
                ble to attack).  The possible arguments have
                been  described  earlier.   The  details  of
                these flags are  described  above.   Use  of
                this option is not recommended.

      DontExpandCnames
                [no  short  name] The standards say that all
                host addresses used in a mail  message  must
                be  fully  canonical.   For example, if your










SMM:08-100         Sendmail Installation and Operation Guide


                host is named "Cruft.Foo.ORG" and  also  has
                an  alias  of "FTP.Foo.ORG", the former name
                must be used at all times.  This is enforced
                during  host  name canonification ($[ ... $]
                lookups).  If this option is set, the proto-
                cols  are  ignored  and the "wrong" thing is
                done.  However, the IETF  is  moving  toward
                changing  this standard, so the behavior may
                become acceptable.  Please note  that  hosts
                downstream  may still rewrite the address to
                be the true canonical name however.

      DontInitGroups
                [no short name] If set, sendmail will  avoid
                using  the  initgroups(3)  call.  If you are
                running NIS, this causes a  sequential  scan
                of  the  groups.byname  map, which can cause
                your NIS server to be badly overloaded in  a
                large  domain.  The cost of this is that the
                only group found for  users  will  be  their
                primary  group  (the  one  in  the  password
                file), which will make file  access  permis-
                sions  somewhat  more  restrictive.   Has no
                effect on  systems  that  don't  have  group
                lists.

      DontProbeInterfaces
                [no  short name] Sendmail normally finds the
                names  of  all  interfaces  active  on  your
                machine  when  it  starts  up and adds their
                name to the $=w class of known host aliases.
                If you have a large number of virtual inter-
                faces or if your  DNS  inverse  lookups  are
                slow  this  can  be  time  consuming.   This
                option turns off that probing.  However, you
                will need to be certain to include all vari-
                ant names in the $=w  class  by  some  other
                mechanism.   If  set  to  loopback, loopback
                interfaces (e.g., lo0) will not be probed.

      DontPruneRoutes
                [R] Normally, sendmail  tries  to  eliminate
                any unnecessary explicit routes when sending
                an error message (as discussed in RFC 1123 S
                5.2.6).   For example, when sending an error
                message to

                    <@known1,@known2,@known3:user@unknown>

                sendmail     will     strip     off      the
                "@known1,@known2" in order to make the route
                as direct as possible.  However,  if  the  R
                option  is  set,  this will be disabled, and










Sendmail Installation and Operation Guide         SMM:08-101


                the mail will be sent to the  first  address
                in  the  route,  even if later addresses are
                known.  This may be useful if you are caught
                behind a firewall.

      DoubleBounceAddress=error-address
                [no  short  name]  If  an  error occurs when
                sending an error  message,  send  the  error
                report  (termed a "double bounce" because it
                is an error "bounce" that occurs when trying
                to send another error "bounce") to the indi-
                cated  address.   The   address   is   macro
                expanded  at  the  time of delivery.  If not
                set, defaults to "postmaster".  If set to an
                empty string, double bounces are dropped.

      EightBitMode=action
                [8]  Set  handling of eight-bit data.  There
                are  two  kinds  of  eight-bit  data:   that
                declared  as  such  using  the BODY=8BITMIME
                ESMTP declaration or the -B8BITMIME  command
                line  flag,  and undeclared 8-bit data, that
                is, input that  just  happens  to  be  eight
                bits.  There are three basic operations that
                can happen: undeclared  8-bit  data  can  be
                automatically  converted  to 8BITMIME, unde-
                clared 8-bit data can be passed as-is  with-
                out  conversion  to  MIME (``just send 8''),
                and declared 8-bit data can be converted  to
                7-bits  for  transmission  to a non-8BITMIME
                mailer.  The possible actions are:

                      s Reject undeclared 8-bit data (``strict'')
                      m Convert undeclared 8-bit data to MIME (``mime'')
                      p Pass undeclared 8-bit data (``pass'')

                In all cases properly declared 8BITMIME data
                will be converted to 7BIT as needed.

      ErrorHeader=file-or-message
                [E]  Prepend  error  messages with the indi-
                cated message.  If it begins with  a  slash,
                it  is  assumed to be the pathname of a file
                containing a message  (this  is  the  recom-
                mended setting).  Otherwise, it is a literal
                message.  The error file might  contain  the
                name,  email address, and/or phone number of
                a local postmaster who could provide  assis-
                tance  to end users.  If the option is miss-
                ing or null, or if it  names  a  file  which
                does  not exist or which is not readable, no
                message is printed.











SMM:08-102         Sendmail Installation and Operation Guide


      ErrorMode=x
                [e] Dispose of errors  using  mode  x.   The
                values for x are:

                    p   Print error messages (default)
                    q   No messages, just give exit status
                    m   Mail back errors
                    w   Write back errors (mail if user not logged in)
                    e   Mail back errors (when applicable) and give zero exit stat always

                Note that the last mode, "e", is for Berknet
                error processing and should not be  used  in
                normal  circumstances.  Note, too, that mode
                "q",  only  applies  to  errors   recognized
                before  sendmail forks for background deliv-
                ery.

      FallbackMXhost=fallbackhost
                [V] If specified, the fallbackhost acts like
                a  very  low  priority MX on every host.  MX
                records will be looked  up  for  this  host,
                unless  the  name  is  surrounded  by square
                brackets.  This is intended to  be  used  by
                sites  with poor network connectivity.  Mes-
                sages which are undeliverable due to  tempo-
                rary  address  failures  (e.g., DNS failure)
                also go to the FallbackMXhost.

      FastSplit [no short name] If set to  a  value  greater
                than  zero  (the  default  is  one), it sup-
                presses the MX  lookups  on  addresses  when
                they  are  initially  sorted,  i.e., for the
                first  delivery   attempt.    This   usually
                results  in faster envelope splitting unless
                the MX records are readily  available  in  a
                local DNS cache.  To enforce initial sorting
                based on MX records set FastSplit  to  zero.
                If  the  mail is submitted directly from the
                command line, then the value also limits the
                number   of   processes   to   deliver   the
                envelopes; if  more  envelopes  are  created
                they  are  only  queued up and must be taken
                care of by a queue run.  Since  the  default
                submission method is via SMTP (either from a
                MUA or via the MSP), the value of  FastSplit
                is  seldom  used to limit the number of pro-
                cesses to deliver the envelopes.

      ForkEachJob
                [Y] If set, deliver each  job  that  is  run
                from the queue in a separate process.












Sendmail Installation and Operation Guide         SMM:08-103


      ForwardPath=path
                [J]  Set  the  path for searching for users'
                .forward files.  The  default  is  "$z/.for-
                ward".   Some sites that use the automounter
                may prefer  to  change  this  to  "/var/for-
                ward/$u" to search a file with the same name
                as the user in a system directory.   It  can
                also be set to a sequence of paths separated
                by colons; sendmail stops at the first  file
                it  can  successfully  and safely open.  For
                example, "/var/forward/$u:$z/.forward"  will
                search  first  in  /var/forward/username and
                then in ~username/.forward (but only if  the
                first file does not exist).

      HelpFile=file
                [H]  Specify  the help file for SMTP.  If no
                file name is specified, "helpfile" is  used.

      HoldExpensive
                [c] If an outgoing mailer is marked as being
                expensive, don't connect immediately.

      HostsFile=path
                [no short name] The path to the hosts  data-
                base, normally "/etc/hosts".  This option is
                only consulted when sendmail is  canonifying
                addresses,  and then only when "files" is in
                the "hosts" service switch entry.   In  par-
                ticular,  this file is never used when look-
                ing up host addresses;  that  is  under  the
                control  of the system gethostbyname(3) rou-
                tine.

      HostStatusDirectory=path
                [no short name] The  location  of  the  long
                term  host  status  information.   When set,
                information about the status of hosts (e.g.,
                host down or not accepting connections) will
                be shared between  all  sendmail  processes;
                normally,  this  information  is  only  held
                within a  single  queue  run.   This  option
                requires a connection cache of at least 1 to
                function.  If the option begins with a lead-
                ing  `/', it is an absolute pathname; other-
                wise, it  is  relative  to  the  mail  queue
                directory.   A  suggested  value  for  sites
                desiring persistent host status  is  ".host-
                stat"  (i.e.,  a  subdirectory  of the queue
                directory).

      IgnoreDots
                [i] Ignore dots in incoming messages.   This










SMM:08-104         Sendmail Installation and Operation Guide


                is always disabled (that is, dots are always
                accepted) when reading SMTP mail.

      InputMailFilters=name,name,...
                A comma  separated  list  of  filters  which
                determines which filters (see the "X -- Mail
                Filter (Milter)  Definitions"  section)  and
                the  invocation  sequence  are contacted for
                incoming SMTP messages.  If none are set, no
                filters will be contacted.

      LDAPDefaultSpec=spec
                [no  short name] Sets a default map specifi-
                cation for LDAP maps.  The value should only
                contain  LDAP  specific settings such as "-h
                host -p port -d bindDN".  The settings  will
                be  used  for all LDAP maps unless the indi-
                vidual map specification  overrides  a  set-
                ting.   This option should be set before any
                LDAP maps are defined.

      LogLevel=n
                [L] Set the log level to n.  Defaults to  9.

      Mxvalue   [no  long version] Set the macro x to value.
                This is intended only for use from the  com-
                mand line.  The -M flag is preferred.

      MailboxDatabase
                [no  short  name]  Type  of  lookup  to find
                information about local mailboxes,  defaults
                to  ``pw'' which uses getpwnam.  Other types
                can be introduced  by  adding  them  to  the
                source code, see libsm/mbdb.c for details.

      UseMSP    [no  short name] Use as mail submission pro-
                gram, i.e., allow group writable queue files
                if  the  group is the same as that of a set-
                group-ID  sendmail  binary.   See  the  file
                sendmail/SECURITY  in  the distribution tar-
                ball.

      MatchGECOS
                [G] Allow fuzzy matching on the GECOS field.
                If this flag is set, and the usual user name
                lookups fail (that is,  there  is  no  alias
                with   this  name  and  a  getpwnam  fails),
                sequentially search the password file for  a
                matching  entry  in  the  GECOS field.  This
                also requires that MATCHGECOS be  turned  on
                during compilation.  This option is not rec-
                ommended.











Sendmail Installation and Operation Guide         SMM:08-105


      MaxAliasRecursion=N
                [no short name] The maximum depth  of  alias
                recursion (default: 10).

      MaxDaemonChildren=N
                [no short name] If set, sendmail will refuse
                connections when it has more than N children
                processing  incoming mail or automatic queue
                runs.  This does not  limit  the  number  of
                outgoing  connections.  If not set, there is
                no limit to the number of children  --  that
                is, the system load averaging controls this.

      MaxHeadersLength=N
                [no short name] The maximum  length  of  the
                sum  of  all  headers.   This can be used to
                prevent a denial  of  service  attack.   The
                default is no limit.

      MaxHopCount=N
                [h]  The  maximum  hop count.  Messages that
                have been processed more than  N  times  are
                assumed  to  be  in a loop and are rejected.
                Defaults to 25.

      MaxMessageSize=N
                [no short name] Specify the maximum  message
                size  to  be  advertised  in  the ESMTP EHLO
                response.  Messages larger than this will be
                rejected.   If  set  to a value greater than
                zero, that value will be listed in the  SIZE
                response,  otherwise  SIZE  is advertised in
                the ESMTP EHLO response without a parameter.

      MaxMimeHeaderLength=N[/M]
                [no  short  name] Sets the maximum length of
                certain MIME header field values to N  char-
                acters.  These MIME header fields are deter-
                mined by being a member of class {checkMIME-
                TextHeaders},  which currently contains only
                the header Content-Description.  For some of
                these  headers  which  take  parameters, the
                maximum length of each parameter is set to M
                if  specified.   If /M is not specified, one
                half of N will be used.  By  default,  these
                values  are 2048 and 1024, respectively.  To
                allow any length, a value of 0 can be speci-
                fied.

      MaxQueueChildren=N
                [no  short  name]  When set, this limits the
                number of concurrent queue runner  processes
                to  N.   This helps to control the amount of










SMM:08-106         Sendmail Installation and Operation Guide


                system resources used  when  processing  the
                queue.  When there are multiple queue groups
                defined and the total number of  queue  run-
                ners  for  these  queue  groups would exceed
                MaxQueueChildren then the queue groups  will
                not all run concurrently. That is, some por-
                tion of the queue groups  will  run  concur-
                rently  such  that MaxQueueChildren will not
                be  exceeded,  while  the  remaining   queue
                groups  will  be  run  later (in round robin
                order). See also MaxRunnersPerQueue and  the
                section  Queue  Group  Declaration.  Notice:
                sendmail does  not  count  individual  queue
                runners, but only sets of processes that act
                on a workgroup.  Hence the actual number  of
                queue  runners  may  be lower than the limit
                imposed by MaxQueueChildren.  This  discrep-
                ancy can be large if some queue runners have
                to wait for  a  slow  server  and  if  short
                intervals are used.

      MaxQueueRunSize=N
                [no  short  name] The maximum number of jobs
                that will be processed  in  a  single  queue
                run.   If  not set, there is no limit on the
                size.  If you have very large  queues  or  a
                very  short queue run interval this could be
                unstable.  However, since the first  N  jobs
                in  queue  directory  order  are run (rather
                than  the  N  highest  priority  jobs)  this
                should  be  set as high as possible to avoid
                "losing" jobs that happen to  fall  late  in
                the queue directory.

      MaxRecipientsPerMessage=N
                [no short name] The maximum number of recip-
                ients that will be accepted per  message  in
                an SMTP transaction.  Note: setting this too
                low can interfere  with  sending  mail  from
                MUAs  that  use SMTP for initial submission.
                If not set, there is no limit on the  number
                of recipients per envelope.

      MaxRunnersPerQueue=N
                [no  short name] This sets the default maxi-
                mum  number  of  queue  runners  for   queue
                groups.   Up to N queue runners will work in
                parallel on a queue group's messages.   This
                is  useful where the processing of a message
                in the queue might delay the  processing  of
                subsequent messages. Such a delay may be the
                result of non-erroneous situations such as a
                low bandwidth connection.  May be overridden










Sendmail Installation and Operation Guide         SMM:08-107


                on a per queue group basis  by  setting  the
                Runners  option; see the section Queue Group
                Declaration.  The default is 1 when not set.

      MeToo     [m] Send to me too, even if I am in an alias
                expansion.  This option  is  deprecated  and
                will be removed from a future version.

      Milter    [no  short  name]  This  option  has several
                sub(sub)options.  The names  of  the  subop-
                tions  are  separated by dots.  At the first
                level the following options are available:

                    LogLevel   Log level for input mail filter actions, defaults to LogLevel.
                    macros     Specifies list of macro to transmit to filters.
                               See list below.

                The ``macros'' option has the following sub-
                options  which  specify the list of macro to
                transmit to milters after  a  certain  event
                occurred.

                    connect   After session connection start
                    helo      After HELO command
                    envfrom   After MAIL FROM command
                    envrcpt   After RCPT TO command

                By  default  the  lists of macros are empty.
                Example:

                    O Milter.LogLevel=12
                    O Milter.macros.connect=j, _, {daemon_name}


      MinFreeBlocks=N
                [b] Insist on at least N blocks free on  the
                filesystem that holds the queue files before
                accepting  email  via  SMTP.   If  there  is
                insufficient  space  sendmail  gives  a  452
                response to the MAIL command.  This  invites
                the sender to try again later.

      MinQueueAge=age
                [no  short  name]  Don't  process any queued
                jobs that have been in the queue  less  than
                the   indicated   time  interval.   This  is
                intended to allow you to get  responsiveness
                by  processing  the  queue fairly frequently
                without thrashing your system by trying jobs
                too often.  The default units are minutes.

      MustQuoteChars=s
                [no  short name] Sets the list of characters










SMM:08-108         Sendmail Installation and Operation Guide


                that must be quoted if used in a  full  name
                that  is  in  the  phrase part of a ``phrase
                <address>'' syntax.  The default is  ``'.''.
                The   characters  ``@,;:\()[]''  are  always
                added to this list.

      NiceQueueRun
                [no short name] The priority of  queue  run-
                ners  (nice(3)).  This value must be greater
                or equal zero.

      NoRecipientAction
                [no short name] The action to take when  you
                receive  a message that has no valid recipi-
                ent headers (To:, Cc:, Bcc:, or  Apparently-
                To:  --  the last included for back compati-
                bility with old sendmails).  It can be  None
                to  pass  the  message  on unmodified, which
                violates the protocol, Add-To to add  a  To:
                header  with  any  recipients it can find in
                the envelope (which might expose Bcc: recip-
                ients),  Add-Apparently-To  to add an Appar-
                ently-To: header (this is only for back-com-
                patibility  and  is  officially deprecated),
                Add-To-Undisclosed  to  add  a  header  "To:
                undisclosed-recipients:;" to make the header
                legal without disclosing anything,  or  Add-
                Bcc to add an empty Bcc: header.

      OldStyleHeaders
                [o]  Assume  that  the headers may be in old
                format, i.e., spaces  delimit  names.   This
                actually  turns on an adaptive algorithm: if
                any  recipient  address  contains  a  comma,
                parenthesis,  or  angle  bracket, it will be
                assumed that commas already exist.  If  this
                flag  is  not on, only commas delimit names.
                Headers  are  always  output   with   commas
                between the names.  Defaults to off.

      OperatorChars=charlist
                [$o  macro]  The list of characters that are
                considered to be "operators", that is, char-
                acters  that  delimit  tokens.  All operator
                characters   are   tokens   by   themselves;
                sequences  of  non-operator  characters  are
                also tokens.  White space  characters  sepa-
                rate tokens but are not tokens themselves --
                for example, "AAA.BBB" has three tokens, but
                "AAA  BBB"  has  two.  If not set, Operator-
                Chars defaults to ".:@[]"; additionally, the
                characters  "()<>,;"  are  always operators.
                Note that OperatorChars must be set  in  the










Sendmail Installation and Operation Guide         SMM:08-109


                configuration file before any rulesets.

      PidFile=filename
                [no  short  name]  Filename of the pid file.
                (default is _PATH_SENDMAILPID).   The  file-
                name  is macro-expanded before it is opened.

      PostmasterCopy=postmaster
                [P] If set, copies of error messages will be
                sent  to  the  named  postmaster.   Only the
                header  of  the  failed  message  is   sent.
                Errors  resulting from messages with a nega-
                tive precedence will  not  be  sent.   Since
                most errors are user problems, this is prob-
                ably not a good idea  on  large  sites,  and
                arguably  contains all sorts of privacy vio-
                lations, but it seems  to  be  popular  with
                certain   operating  systems  vendors.   The
                address is macro expanded  at  the  time  of
                delivery.  Defaults to no postmaster copies.

      PrivacyOptions=opt,opt,...
                [p] Set the privacy options.  ``Privacy'' is
                really  a misnomer; many of these are just a
                way of insisting on  stricter  adherence  to
                the  SMTP  protocol.   The  options  can  be
                selected from:

                    public         Allow open access
                    needmailhelo   Insist on HELO or EHLO command before MAIL
                    needexpnhelo   Insist on HELO or EHLO command before EXPN
                    noexpn         Disallow EXPN entirely, implies noverb.
                    needvrfyhelo   Insist on HELO or EHLO command before VRFY
                    novrfy         Disallow VRFY entirely
                    noetrn         Disallow ETRN entirely
                    noverb         Disallow VERB entirely
                    restrictmailq  Restrict mailq command
                    restrictqrun   Restrict -q command line flag
                    restrictexpand Restrict -bv and -v command line flags
                    noreceipts     Don't return success DSNs[20]
                    nobodyreturn   Don't return the body of a message with DSNs
                    goaway         Disallow essentially all SMTP status queries
                    authwarnings   Put X-Authentication-Warning: headers in messages
                                   and log warnings

                The  "goaway"  pseudo-flag  sets  all  flags
                except    "noreceipts",     "restrictmailq",
                "restrictqrun",  "restrictexpand", "noetrn",
____________________
   [20]N.B.: the noreceipts flag turns off support  for  RFC
1891 (Delivery Status Notification).












SMM:08-110         Sendmail Installation and Operation Guide


                and "nobodyreturn".  If mailq is restricted,
                only  people  in the same group as the queue
                directory can print  the  queue.   If  queue
                runs are restricted, only root and the owner
                of the queue directory can  run  the  queue.
                The  "restrictexpand"  pseudo-flag instructs
                sendmail to drop  privileges  when  the  -bv
                option  is  given  by  users who are neither
                root nor the  TrustedUser  so  users  cannot
                read private aliases, forwards, or :include:
                files.  It will add the "NonRootSafeAddr" to
                the  "DontBlameSendmail"  option  to prevent
                misleading unsafe address warnings.  It also
                overrides  the  -v  (verbose)  command  line
                option  to  prevent   information   leakage.
                Authentication  Warnings  add warnings about
                various   conditions   that   may   indicate
                attempts  to  spoof the mail system, such as
                using a non-standard queue directory.

      ProcessTitlePrefix=string
                [no short name]  Prefix  the  process  title
                shown  on  'ps'  listings  with string.  The
                string will be macro processed.

      QueueDirectory=dir
                [Q] The  QueueDirectory  option  serves  two
                purposes.  First, it specifies the directory
                or set  of  directories  that  comprise  the
                default  queue  group.  Second, it specifies
                the directory D which is the ancestor of all
                queue  directories,  and which sendmail uses
                as  its  current  working  directory.   When
                sendmail  dumps  core,  it  leaves  its core
                files in D.  There are two  cases.   If  dir
                ends      with      an     asterisk     (eg,
                /var/spool/mqueue/qd*),  then  all  of   the
                directories or symbolic links to directories
                beginning  with  `qd'  in  /var/spool/mqueue
                will  be  used  as  queue directories of the
                default queue group,  and  /var/spool/mqueue
                will  be  used  as  the working directory D.
                Otherwise, dir must name a  directory  (usu-
                ally  /var/spool/mqueue):  the default queue
                group consists of the single queue directory
                dir,  and  the working directory D is set to
                dir.  To define additional groups  of  queue
                directories,  use the configuration file `Q'
                command.  Do not change the queue  directory
                structure while sendmail is running.

      QueueFactor=factor
                [q]  Use factor as the multiplier in the map










Sendmail Installation and Operation Guide         SMM:08-111


                function to decide when  to  just  queue  up
                jobs  rather  than  run them.  This value is
                divided by the difference between  the  cur-
                rent load average and the load average limit
                (QueueLA option) to  determine  the  maximum
                message   priority   that   will   be  sent.
                Defaults to 600000.

      QueueLA=LA
                [x] When the system load average exceeds  LA
                and  the  QueueFactor  (q) option divided by
                the difference in the current  load  average
                and the QueueLA option plus one is less than
                the priority of the message, just queue mes-
                sages   (i.e.,  don't  try  to  send  them).
                Defaults to 8 multiplied by  the  number  of
                processors online on the system (if that can
                be determined).

      QueueFileMode=mode
                [no  short  name]  Default  permissions  for
                queue  files  (octal).  If not set, sendmail
                uses 0600 unless its real and effective  uid
                are different in which case it uses 0644.

      QueueSortOrder=algorithm
                [no  short name] Sets the algorithm used for
                sorting the queue.  Only the first character
                of  the  value  is  used.   Legal values are
                "host" (to order by the name  of  the  first
                host  name  of  the first recipient), "file-
                name" (to order by the  name  of  the  queue
                file  name), "time" (to order by the submis-
                sion/creation time), "random" (to order ran-
                domly), "modification" (to order by the mod-
                ification time of the qf file (older entries
                first)), and "priority" (to order by message
                priority).  Host ordering makes  better  use
                of  the  connection  cache,  but may tend to
                process low priority messages that go  to  a
                single host over high priority messages that
                go to several hosts; it  probably  shouldn't
                be used on slow network links.  Filename and
                modification time ordering saves  the  over-
                head  of  reading  all  of  the queued items
                before starting  the  queue  run.   Creation
                (submission)  time ordering is almost always
                a bad idea, since it allows large, bulk mail
                to go out before smaller, personal mail, but
                may have applicability on  some  hosts  with
                very  fast connections.  Random is useful if
                several queue runners are  started  by  hand
                which try to drain the same queue since odds










SMM:08-112         Sendmail Installation and Operation Guide


                are they will be working on different  parts
                of  the  queue  at  the same time.  Priority
                ordering is the default.

      QueueTimeout=timeout
                [T]  A  synonym  for  "Timeout.queuereturn".
                Use  that form instead of the "QueueTimeout"
                form.

      RandFile  [no short name] Name of file containing ran-
                dom  data  or the name of the UNIX socket if
                EGD is used.  A (required) prefix "egd:"  or
                "file:"   specifies   the   type.   STARTTLS
                requires this filename if the  compile  flag
                HASURANDOMDEV   is   not   set   (see  send-
                mail/README).

      ResolverOptions=options
                [I] Set resolver options.  Values can be set
                using  +flag  and  cleared  using -flag; the
                flags can  be  "debug",  "aaonly",  "usevc",
                "primary",  "igntc",  "recurse", "defnames",
                "stayopen", "use_inet6", or  "dnsrch".   The
                string  "HasWildcardMX"  (without  a + or -)
                can  be  specified  to  turn  off   matching
                against MX records when doing name canonifi-
                cations.  The string  "WorkAroundBrokenAAAA"
                (without  a + or -) can be specified to work
                around some broken nameservers which  return
                SERVFAIL  (a  temporary  failure)  on T_AAAA
                (IPv6) lookups.  Notice: it might be  neces-
                sary  to apply the same (or similar) options
                to submit.cf too.

      RrtImpliesDsn
                [R]  If  this  option  is  set,  a  "Return-
                Receipt-To:"  header causes the request of a
                DSN, which is sent to the envelope sender as
                required  by  RFC  1891,  not to the address
                given in the header.

      RunAsUser=user
                [no short name] The user parameter may be  a
                user  name  (looked  up in /etc/passwd) or a
                numeric  user  id;  either  form  can   have
                ":group"   attached   (where  group  can  be
                numeric or symbolic).  If set to a  non-zero
                (non-root)  value,  sendmail  will change to















Sendmail Installation and Operation Guide         SMM:08-113


                this  user  id  shortly  after  startup[21].
                This  avoids  a  certain  class  of security
                problems.   However,  this  means  that  all
                ".forward"  and  ":include:"  files  must be
                readable by the indicated user and all files
                to be written must be writable by user Also,
                all file  and  program  deliveries  will  be
                marked  unsafe  unless the option DontBlame-
                Sendmail=NonRootSafeAddr is  set,  in  which
                case  the delivery will be done as user.  It
                is also incompatible with the  SafeFileEnvi-
                ronment  option.  In other words, it may not
                actually add much to security on an  average
                system,  and  may in fact detract from secu-
                rity (because other file permissions must be
                loosened).   However, it should be useful on
                firewalls and other places where users don't
                have  accounts  and the aliases file is well
                constrained.

      RecipientFactor=fact
                [y] The indicated factor  is  added  to  the
                priority  (thus lowering the priority of the
                job) for each recipient,  i.e.,  this  value
                penalizes jobs with large numbers of recipi-
                ents.  Defaults to 30000.

      RefuseLA=LA
                [X] When the system load average exceeds LA,
                refuse  incoming SMTP connections.  Defaults
                to 12 multiplied by the number of processors
                online  on the system (if that can be deter-
                mined).

      RetryFactor=fact
                [Z] The factor  is  added  to  the  priority
                every  time  a job is processed.  Thus, each
                time a job is processed, its  priority  will
                be  decreased  by  the  indicated value.  In
                most environments this should  be  positive,
                since  hosts that are down are all too often
                down for a long time.  Defaults to 90000.

      SafeFileEnvironment=dir
                [no short name] If this option is set, send-
                mail will do a chroot(2) call into the indi-
                cated  directory  before  doing   any   file
                writes.   If  the file name specified by the
____________________
   [21]When running as a daemon, it changes to this user af-
ter  accepting a connection but before reading any SMTP com-
mands.











SMM:08-114         Sendmail Installation and Operation Guide


                user begins with dir, that partial path name
                will be stripped off before writing, so (for
                example) if the SafeFileEnvironment variable
                is   set   to   "/safe"   then   aliases  of
                "/safe/logs/file" and "/logs/file"  actually
                indicate  the  same  file.  Additionally, if
                this option  is  set,  sendmail  refuses  to
                deliver to symbolic links.

      SaveFromLine
                [f]  Save  UNIX-style  "From"  lines  at the
                front of headers.  Normally they are assumed
                redundant and discarded.

      SharedMemoryKey
                [no short name] Key to use for shared memory
                segment; if not set (or  0),  shared  memory
                will  not  be  used.   Requires  support for
                shared memory to be compiled into  sendmail.
                If  this  option  is set, sendmail can share
                some data between different instances.   For
                example,  the  number  of entries in a queue
                directory or the available space in  a  file
                system.  This allows for more efficient pro-
                gram execution, since only one process needs
                to  update the data instead of each individ-
                ual process gathering the data each time  it
                is required.

      SendMimeErrors
                [j] If set, send error messages in MIME for-
                mat (see RFC 2045 and RFC 1344 for details).
                If  disabled,  sendmail  will not return the
                DSN keyword in response to an EHLO and  will
                not do Delivery Status Notification process-
                ing as described in RFC 1891.

      ServerCertFile
                [no short name] File containing the certifi-
                cate  of  the server, i.e., this certificate
                is used when sendmail acts as  server  (used
                for STARTTLS).

      ServerKeyFile
                [no  short name] File containing the private
                key  belonging  to  the  server  certificate
                (used for STARTTLS).

      ServiceSwitchFile=filename
                [no  short name] If your host operating sys-
                tem has a service switch abstraction  (e.g.,
                /etc/nsswitch.conf     on     Solaris     or
                /etc/svc.conf on Ultrix and DEC OSF/1)  that










Sendmail Installation and Operation Guide         SMM:08-115


                service will be consulted and this option is
                ignored.  Otherwise, this is the name  of  a
                file  that provides the list of methods used
                to implement particular services.  The  syn-
                tax is a series of lines, each of which is a
                sequence of words.  The first  word  is  the
                service  name,  and following words are ser-
                vice types.  The services that sendmail con-
                sults  directly  are  "aliases" and "hosts."
                Service types can  be  "dns",  "nis",  "nis-
                plus",  or "files" (with the caveat that the
                appropriate  support  must  be  compiled  in
                before  the  service can be referenced).  If
                ServiceSwitchFile  is  not   specified,   it
                defaults  to  /etc/mail/service.switch.   If
                that file does not exist, the default switch
                is:

                    aliases        files
                    hosts          dns nis files

                The    default   file   is   "/etc/mail/ser-
                vice.switch".

      SevenBitInput
                [7] Strip input to seven bits  for  compati-
                bility  with old systems.  This shouldn't be
                necessary.

      SingleLineFromHeader
                [no short name] If  set,  From:  lines  that
                have  embedded  newlines  are unwrapped onto
                one line.  This is to get around a botch  in
                Lotus  Notes  that  apparently cannot under-
                stand legally wrapped RFC 822 headers.

      SingleThreadDelivery
                [no short name] If  set,  a  client  machine
                will  never try to open two SMTP connections
                to a single server machine at the same time,
                even  in  different  processes.  That is, if
                another sendmail is already talking to  some
                host  a  new  sendmail will not open another
                connection.   This  property  is  of   mixed
                value; although this reduces the load on the
                other machine,  it  can  cause  mail  to  be
                delayed  (for  example,  if  one sendmail is
                delivering a huge message,  other  sendmails
                won't  be able to send even small messages).
                Also, it requires  another  file  descriptor
                (for  the  lock file) per connection, so you
                may have to reduce  the  ConnectionCacheSize
                option  to  avoid running out of per-process










SMM:08-116         Sendmail Installation and Operation Guide


                file descriptors.  Requires the  HostStatus-
                Directory option.

      SmtpGreetingMessage=message
                [$e macro] The message printed when the SMTP
                server starts up.  Defaults to "$j  Sendmail
                $v ready at $b".

      StatusFile=file
                [S]  Log  summary  statistics  in  the named
                file.  If no file name is  specified,  "sta-
                tistics"  is  used.   If not set, no summary
                statistics are saved.  This  file  does  not
                grow  in  size.  It can be printed using the
                mailstats(8) program.

      SuperSafe [s] This option can be set to  True,  False,
                or  Interactive.   If  set to True, sendmail
                will  be  super-safe  when  running  things,
                i.e.,  always  instantiate  the  queue file,
                even if you are going to  attempt  immediate
                delivery.   Sendmail always instantiates the
                queue file before returning control  to  the
                client under any circumstances.  This should
                really always be set to True.  The  Interac-
                tive  value  has been introduced in 8.12 and
                can be used  together  with  DeliveryMode=i.
                It  skips  some  synchronization calls which
                are effectively doubled in the  code  execu-
                tion path for this mode.

      TLSSrvOptions
                [no  short  name]  List  of options for SMTP
                STARTTLS for the server consisting of single
                characters  with  intervening white space or
                commas.  The flag ``V'' disables client ver-
                ification,  and  hence it is not possible to
                use a client certificate for relaying.  Cur-
                rently there are no other flags available.

      TempFileMode=mode
                [F]  The  file  mode  for  transcript files,
                files to which sendmail  delivers  directly,
                files  in  the HostStatusDirectory, and Sta-
                tusFile.  It  is  interpreted  in  octal  by
                default.  Defaults to 0600.

      Timeout.type=timeout
                [r; subsumes old T option as well] Set time-
                out values.  For more information, see  sec-
                tion 4.1.












Sendmail Installation and Operation Guide         SMM:08-117


      TimeZoneSpec=tzinfo
                [t]  Set  the local time zone info to tzinfo
                -- for  example,  "PST8PDT".   Actually,  if
                this is not set, the TZ environment variable
                is cleared (so the system default is  used);
                if  set  but null, the user's TZ variable is
                used, and if set and non-null the  TZ  vari-
                able is set to this value.

      TrustedUser=user
                [no  short name] The user parameter may be a
                user name (looked up in  /etc/passwd)  or  a
                numeric user id.  Trusted user for file own-
                ership and starting  the  daemon.   If  set,
                generated  alias  databases  and the control
                socket (if configured) will automatically be
                owned by this user.

      TryNullMXList
                [w]  If  this system is the "best" (that is,
                lowest preference) MX for a given host,  its
                configuration  rules  should normally detect
                this situation and treat that condition spe-
                cially  by  forwarding  the  mail  to a UUCP
                feed, treating it  as  local,  or  whatever.
                However,  in  some  cases  (such as Internet
                firewalls) you may want to  try  to  connect
                directly to that host as though it had no MX
                records at all.  Setting this option  causes
                sendmail  to try this.  The downside is that
                errors in your configuration are  likely  to
                be  diagnosed  as "host unknown" or "message
                timed out" instead of something  more  mean-
                ingful.  This option is disrecommended.

      UnixFromLine=fromline
                [$l  macro]  Defines  the  format  used when
                sendmail must add a  UNIX-style  From_  line
                (that      is,      a     line     beginning
                "From<space>user").  Defaults  to  "From  $g
                $d".   Don't  change this unless your system
                uses a different UNIX mailbox  format  (very
                unlikely).

      UnsafeGroupWrites
                [no  short name] If set (default), :include:
                and .forward files that are  group  writable
                are  considered "unsafe", that is, they can-
                not reference programs or write directly  to
                files.   World  writable :include: and .for-
                ward files are  always  unsafe.   Note:  use
                DontBlameSendmail  instead;  this  option is
                deprecated.










SMM:08-118         Sendmail Installation and Operation Guide


      UseErrorsTo
                [l] If there is an "Errors-To:" header, send
                error   messages  to  the  addresses  listed
                there.  They normally  go  to  the  envelope
                sender.   Use of this option causes sendmail
                to violate RFC 1123.  This option is disrec-
                ommended and deprecated.

      UserDatabaseSpec=udbspec
                [U] The user database specification.

      Verbose   [v]  Run  in  verbose mode.  If this is set,
                sendmail adjusts options HoldExpensive  (old
                c) and DeliveryMode (old d) so that all mail
                is delivered completely in a single  job  so
                that   you   can  see  the  entire  delivery
                process.  Option Verbose should never be set
                in  the  configuration  file; it is intended
                for command line use only.

      XscriptFileBufferSize=threshold
                [no short name] Set the threshold, in bytes,
                before  a memory-based queue transcript file
                becomes disk-based.   The  default  is  4096
                bytes.

      All options can be specified on the command line using
      the -O or -o flag, but most  will  cause  sendmail  to
      relinquish  its  set-user-ID permissions.  The options
      that will not cause this are SevenBitInput [7], Eight-
      BitMode  [8],  MinFreeBlocks  [b],  CheckpointInterval
      [C], DeliveryMode [d], ErrorMode [e], IgnoreDots  [i],
      SendMimeErrors [j], LogLevel [L], MeToo [m], OldStyle-
      Headers [o], PrivacyOptions [p], SuperSafe  [s],  Ver-
      bose [v], QueueSortOrder, MinQueueAge, DefaultCharSet,
      Dial    Delay,    NoRecipientAction,    ColonOkInAddr,
      MaxQueueRunSize,  SingleLineFromHeader,  and  AllowBo-
      gusHELO.  Actually, PrivacyOptions [p]  given  on  the
      command  line  are added to those already specified in
      the sendmail.cf  file,  i.e.,  they  can't  be  reset.
      Also, M (define macro) when defining the r or s macros
      is also considered "safe".

   5.7.  P -- Precedence Definitions

           Values for the "Precedence:" field may be defined
      using  the  P  control line.  The syntax of this field
      is:

          Pname=num

      When the name is found in a "Precedence:"  field,  the
      message  class  is  set  to  num.  Higher numbers mean










Sendmail Installation and Operation Guide         SMM:08-119


      higher precedence.  Numbers less than  zero  have  the
      special  property  that if an error occurs during pro-
      cessing the body of the message will not be  returned;
      this  is  expected  to be used for "bulk" mail such as
      through mailing  lists.   The  default  precedence  is
      zero.  For example, our list of precedences is:

          Pfirst-class=0
          Pspecial-delivery=100
          Plist=-30
          Pbulk=-60
          Pjunk=-100

      People  writing  mailing list exploders are encouraged
      to use "Precedence: list".  Older versions of sendmail
      (which discarded all error returns for negative prece-
      dences)  didn't  recognize  this  name,  giving  it  a
      default  precedence  of  zero.  This allows list main-
      tainers to see error returns on both old and new  ver-
      sions of sendmail.

   5.8.  V -- Configuration Version Level

           To  provide  compatibility with old configuration
      files, the V line has been added to define  some  very
      basic  semantics of the configuration file.  These are
      not intended to be long term  supports;  rather,  they
      describe compatibility features which will probably be
      removed in future releases.

           N.B.: these version levels  have  nothing  to  do
      with the version number on the files.  For example, as
      of this writing version 10 config files (specifically,
      8.10) used version level 9 configurations.

           "Old"  configuration files are defined as version
      level one.  Version level two files make the following
      changes:

       (1)   Host  name canonification ($[ ... $]) appends a
             dot if the name is recognized; this  gives  the
             config  file  a  way of finding out if anything
             matched.  (Actually, this just initializes  the
             "host"  map  with  the  "-a."   flag -- you can
             reset it to anything you  prefer  by  declaring
             the map explicitly.)

       (2)   Default   host  name  extension  is  consistent
             throughout processing; version level  one  con-
             figurations  turned  off domain extension (that
             is, adding the local domain name)  during  cer-
             tain  points  in processing.  Version level two
             configurations  are  expected  to   include   a










SMM:08-120         Sendmail Installation and Operation Guide


             trailing  dot  to  indicate  that  the  name is
             already canonical.

       (3)   Local names that are  not  aliases  are  passed
             through  a new distinguished ruleset five; this
             can be used to  append  a  local  relay.   This
             behavior  can  be  prevented  by  resolving the
             local name with an initial `@'.  That is, some-
             thing  that  resolves  to  a local mailer and a
             user name of "vikki"  will  be  passed  through
             ruleset  five, but a user name of "@vikki" will
             have the  `@'  stripped,  will  not  be  passed
             through  ruleset  five,  but  will otherwise be
             treated the same as  the  prior  example.   The
             expectation  is  that  this  might  be  used to
             implement a policy where mail sent  to  "vikki"
             was  handled by a central hub, but mail sent to
             "vikki@localhost" was delivered directly.

           Version level three files allow # initiated  com-
      ments  on all lines.  Exceptions are backslash escaped
      # marks and the $# syntax.

           Version level four configurations are  completely
      equivalent to level three for historical reasons.

           Version level five configuration files change the
      default definition of $w to be just the  first  compo-
      nent of the hostname.

           Version level six configuration files change many
      of the local processing options (such as aliasing  and
      matching  the beginning of the address for `|' charac-
      ters) to be mailer  flags;  this  allows  fine-grained
      control  over the special local processing.  Level six
      configuration files may also use  long  option  names.
      The  ColonOkInAddr  option  (to  allow  colons  in the
      local-part of addresses) defaults on  for  lower  num-
      bered  configuration  files;  the  configuration  file
      requires some additional intelligence to properly han-
      dle the RFC 822 group construct.

           Version  level seven configuration files used new
      option names to replace old macros  ($e  became  Smtp-
      GreetingMessage, $l became UnixFromLine, and $o became
      OperatorChars.  Also, prior to version seven, the  F=q
      flag  (use  250  instead  of 252 return value for SMTP
      VRFY commands) was assumed.

           Version level eight configuration files allow  $#
      on the left hand side of ruleset lines.












Sendmail Installation and Operation Guide         SMM:08-121


           Version  level  nine  configuration  files  allow
      parentheses in rulesets, i.e. they are not treated  as
      comments and hence removed.

           Version level ten configuration files allow queue
      group definitions.

           The V line may have an optional /vendor to  indi-
      cate  that  this configuration file uses modifications
      specific  to  a  particular  vendor[22].   You may use
      "/Berkeley" to emphasize that this configuration  file
      uses the Berkeley dialect of sendmail.

   5.9.  K -- Key File Declaration

           Special maps can be defined using the line:

          Kmapname mapclass arguments

      The  mapname is the handle by which this map is refer-
      enced in the rewriting rules.   The  mapclass  is  the
      name  of a type of map; these are compiled in to send-
      mail.  The arguments are interpreted depending on  the
      class;  typically,  there  would  be a single argument
      naming the file containing the map.

           Maps are referenced using the syntax:

          $( map key $@ arguments $: default $)

      where either or both of the arguments or default  por-
      tion may be omitted.  The $@ arguments may appear more
      than once.  The indicated key and arguments are passed
      to  the appropriate mapping function.  If it returns a
      value, it replaces the input.  If it does not return a
      value  and  the  default  is  specified,  the  default
      replaces  the  input.    Otherwise,   the   input   is
      unchanged.

           The arguments are passed to the map for arbitrary
      use.  Most map classes can interpolate these arguments
      into  their values using the syntax "%n" (where n is a
      digit) to indicate the corresponding argument.   Argu-
      ment  "%0"  indicates  the database key.  For example,
      the rule

____________________
   [22]And of course, vendors are encouraged  to  add  them-
selves to the list of recognized vendors by editing the rou-
tine setvendor in  conf.c.   Please  send  e-mail  to  send-
mail@Sendmail.ORG to register your vendor dialect.












SMM:08-122         Sendmail Installation and Operation Guide


          R$- ! $+       $: $(uucp $1 $@ $2 $: $2 @ $1 . UUCP $)

      Looks up the UUCP name in a (user defined)  UUCP  map;
      if not found it turns it into ".UUCP" form.  The data-
      base might contain records like:

          decvax         %1@%0.DEC.COM
          research       %1@%0.ATT.COM

      Note that default clauses never do this mapping.

           The built-in map with both name and class  "host"
      is  the  host name canonicalization lookup.  Thus, the
      syntax:

          $(host hostname$)

      is equivalent to:

          $[hostname$]


           There are many defined classes.

      dbm       Database lookups using the ndbm(3)  library.
                Sendmail must be compiled with NDBM defined.

      btree     Database lookups using the  btree  interface
                to  the  Berkeley DB library.  Sendmail must
                be compiled with NEWDB defined.

      hash      Database lookups using the hash interface to
                the  Berkeley  DB library.  Sendmail must be
                compiled with NEWDB defined.

      nis       NIS lookups.  Sendmail must be compiled with
                NIS defined.

      nisplus   NIS+  lookups.   Sendmail  must  be compiled
                with NISPLUS defined.  The argument  is  the
                name  of  the  table to use for lookups, and
                the -k and -v flags may be used to  set  the
                key and value columns respectively.

      hesiod    Hesiod  lookups.   Sendmail must be compiled
                with HESIOD defined.

      ldap      LDAP X500 directory lookups.  Sendmail  must
                be  compiled  with LDAPMAP defined.  The map
                supports most of the standard arguments  and
                most  of  the  command line arguments of the
                ldapsearch program.  Note that, by  default,
                if  a  single query matches multiple values,










Sendmail Installation and Operation Guide         SMM:08-123


                only the first value will be returned unless
                the  -z  (value  separator) map flag is set.
                Also, the -1 map flag will treat a  multiple
                value return as if there were no matches.

      netinfo   NeXT NetInfo lookups.  Sendmail must be com-
                piled with NETINFO defined.

      text      Text file lookups.  The format of  the  text
                file  is  defined  by the -k (key field num-
                ber), -v (value field number), and -z (field
                delimiter) flags.

      ph        PH  query map.  Contributed and supported by
                Mark Roth, roth@uiuc.edu.  For more informa-
                tion,  consult  the  web  site  "http://www-
                dev.cites.uiuc.edu/sendmail/".

      nsd       nsd map for IRIX 6.5 and later.  Contributed
                and   supported   by   Bob   Mende  of  SGI,
                mende@sgi.com.

      stab      Internal symbol table lookups.  Used  inter-
                nally for aliasing.

      implicit  Really  should  be called "alias" -- this is
                used to get the default  lookups  for  alias
                files,  and  is  the  default if no class is
                specified for alias files.

      user      Looks up users using  getpwnam(3).   The  -v
                flag  can be used to specify the name of the
                field to return (although this  is  normally
                used only to check the existence of a user).

      host      Canonifies host domain names.  Given a  host
                name  it  calls  the name server to find the
                canonical name for that host.

      bestmx    Returns the best MX record for a  host  name
                given  as  the  key.  The current machine is
                always preferred -- that is, if the  current
                machine is one of the hosts listed as a low-
                est-preference MX record, then  it  will  be
                guaranteed to be returned.  This can be used
                to find out if this machine  is  the  target
                for  an  MX record, and mail can be accepted
                on that basis.  If the  -z  flag  is  given,
                then all MX names are returned, separated by
                the given delimiter.

      dns       This map requires the option -R  to  specify
                the  DNS resource record type to lookup. The










SMM:08-124         Sendmail Installation and Operation Guide


                following  types  are  supported:  A,  AAAA,
                AFSDB,  CNAME, MX, NS, PTR, SRV, and TXT.  A
                map lookup  will  return  only  one  record.
                Hence  for some types, e.g., MX records, the
                return value might be a  random  element  of
                the  list  due  to  randomizing  in  the DNS
                resolver.

      sequence  The arguments on the `K' line are a list  of
                maps;  the  resulting map searches the argu-
                ment maps in order until it  finds  a  match
                for  the indicated key.  For example, if the
                key definition is:

                    Kmap1 ...
                    Kmap2 ...
                    Kseqmap sequence map1 map2

                then a lookup against "seqmap" first does  a
                lookup  in  map1.   If  that  is  found,  it
                returns immediately.   Otherwise,  the  same
                key is used for map2.

      syslog    the  key  is  logged  via  syslogd(8).   The
                lookup returns the empty string.

      switch    Much like the "sequence" map except that the
                order  of  maps is determined by the service
                switch.  The argument is  the  name  of  the
                service to be looked up; the values from the
                service switch are appended to the map  name
                to  create new map names.  For example, con-
                sider the key definition:

                    Kali switch aliases

                together with the service switch entry:

                    aliases        nis files

                This causes a query against the map "ali" to
                search  maps named "ali.nis" and "ali.files"
                in that order.

      dequote   Strip double quotes (")  from  a  name.   It
                does  not  strip  backslashes,  and will not
                strip quotes if the resulting  string  would
                contain  unscannable  syntax (that is, basic
                errors like unbalanced angle brackets;  more
                sophisticated  errors  such as unknown hosts
                are not checked).  The  intent  is  for  use
                when trying to accept mail from systems such
                as DECnet that routinely  quote  odd  syntax










Sendmail Installation and Operation Guide         SMM:08-125


                such as

                    "49ers::ubell"

                A typical usage is probably something like:

                    Kdequote dequote

                    ...

                    R$-            $: $(dequote $1 $)
                    R$- $+         $: $>3 $1 $2

                Care  must  be  taken  to prevent unexpected
                results; for example,

                    "|someprogram < input > output"

                will have quotes stripped, but the result is
                probably  not  what you had in mind.  Fortu-
                nately these cases are rare.

      regex     The map definition on the K line contains  a
                regular  expression.   Any key input is com-
                pared to that  expression  using  the  POSIX
                regular   expressions   routines  regcomp(),
                regerr(), and regexec().  Refer to the docu-
                mentation for those routines for more infor-
                mation about the regular  expression  match-
                ing.  No rewriting of the key is done if the
                -m flag is used.  Without  it,  the  key  is
                discarded  or  if  -s if used, it is substi-
                tuted by the substring matches, delimited by
                $|  or  the string specified with the the -d
                flag.  The flags available for the map are

                    -n  not
                    -f  case sensitive
                    -b  basic regular expressions (default is extended)
                    -s  substring match
                    -d  set the delimiter used for -s
                    -a  append string to key
                    -m  match only, do not replace/discard value
                    -D  perform no lookup in deferred delivery mode.

                The -s flag can include an optional  parame-
                ter  which  can  be  used to select the sub-
                strings in the result of  the  lookup.   For
                example,

                    -s1,3,4

                Notes: to match a $ in a string, \$$ must be










SMM:08-126         Sendmail Installation and Operation Guide


                used.  If the pattern contains spaces,  they
                must be replaced with the blank substitution
                character, unless it is space itself.

      program   The arguments on the K line are the pathname
                to  a  program and any initial parameters to
                be passed.  When the map is called, the  key
                is  added  to the initial parameters and the
                program is invoked as the default user/group
                id.   The  first  line of standard output is
                returned as the value of the  lookup.   This
                has  many  potential  security problems, and
                has terrible performance; it should be  used
                only when absolutely necessary.

      macro     Set or clear a macro value.  To set a macro,
                pass the value as the first argument in  the
                map  lookup.   To clear a macro, do not pass
                an argument in  the  map  lookup.   The  map
                always returns the empty string.  Example of
                typical usage include:

                    Kstorage macro

                    ...

                    # set macro ${MyMacro} to the ruleset match
                    R$+ $: $(storage {MyMacro} $@ $1 $) $1
                    # set macro ${MyMacro} to an empty string
                    R$* $: $(storage {MyMacro} $@ $) $1
                    # clear macro ${MyMacro}
                    R$- $: $(storage {MyMacro} $) $1


      arith     Perform simple arithmetic  operations.   The
                operation  is  given as key, currently +, -,
                *, /, %, |, & (bitwise OR, AND), l (for less
                than),  and  = are supported.  The two oper-
                ands are given  as  arguments.   The  lookup
                returns  the result of the computation, i.e.
                TRUE or FALSE for comparisons, integer  val-
                ues otherwise.  All options which are possi-
                ble for maps are ignored.  A simple  example
                is:

                    Kcomp arith

                    ...

                    Scheck_etrn
                    R$* $: $(comp l $@ $&{load_avg} $@ 7 $) $1
                    RFALSE$# error ...











Sendmail Installation and Operation Guide         SMM:08-127


           Most  of  these  accept  as  arguments  the  same
      optional flags and a filename (or a mapname  for  NIS;
      the filename is the root of the database path, so that
      ".db" or some  other  extension  appropriate  for  the
      database type will be added to get the actual database
      name).  Known flags are:

      -o        Indicates that this map is optional --  that
                is, if it cannot be opened, no error is pro-
                duced, and sendmail will behave  as  if  the
                map existed but was empty.

      -N, -O    If  neither -N or -O are specified, sendmail
                uses an adaptive algorithm to decide whether
                or  not to look for null bytes on the end of
                keys.  It starts by trying both; if it finds
                any  key  with  a  null  byte it never tries
                again without a null byte  and  vice  versa.
                If  -N is specified it never tries without a
                null byte and if -O is  specified  it  never
                tries  with  a  null  byte.   Setting one of
                these can speed matches but are never neces-
                sary.   If  both  -N  and  -O are specified,
                sendmail will never try any matches  at  all
                --  that is, everything will appear to fail.

      -ax       Append the string x on  successful  matches.
                For  example, the default host map appends a
                dot on successful matches.

      -Tx       Append the string x on  temporary  failures.
                For  example,  x  would be appended if a DNS
                lookup returned "server failed"  or  an  NIS
                lookup  could not locate a server.  See also
                the -t flag.

      -f        Do not fold upper to lower case before look-
                ing up the key.

      -m        Match  only  (without  replacing the value).
                If you only care about the  existence  of  a
                key  and  not  the  value (as you might when
                searching the  NIS  map  "hosts.byname"  for
                example),  this  flag  prevents the map from
                substituting the  value.   However,  The  -a
                argument  is  still appended on a match, and
                the default is  still  taken  if  the  match
                fails.

      -kkeycol  The  key  column  name  (for NIS+) or number
                (for text lookups).  For LDAP maps  this  is
                an   LDAP  filter  string  in  which  %s  is
                replaced with the literal  contents  of  the










SMM:08-128         Sendmail Installation and Operation Guide


                lookup  key and %0 is replaced with the LDAP
                escaped contents of the lookup key according
                to RFC 2254.

      -vvalcol  The  value  column name (for NIS+) or number
                (for text lookups).  For LDAP maps  this  is
                the  name  of  one  or more attributes to be
                returned; multiple attributes can  be  sepa-
                rated  by  commas.   If  not  specified, all
                attributes  found  in  the  match  will   be
                returned.

      -zdelim   The column delimiter (for text lookups).  It
                can be a single character or one of the spe-
                cial  strings  "\n" or "\t" to indicate new-
                line  or  tab  respectively.    If   omitted
                entirely,   the   column  separator  is  any
                sequence of white space.  For LDAP maps this
                is the separator character to combine multi-
                ple values into a single return string.   If
                not  set,  the  LDAP lookup will only return
                the first match found.

      -t        Normally, when a map attempts to do a lookup
                and   the   server   fails  (e.g.,  sendmail
                couldn't contact any name  server;  this  is
                not  the same as an entry not being found in
                the map), the  message  being  processed  is
                queued  for  future processing.  The -t flag
                turns off this behavior, letting the  tempo-
                rary  failure (server down) act as though it
                were a permanent failure (entry not  found).
                It  is  particularly useful for DNS lookups,
                where  someone  else's  misconfigured   name
                server  can  cause problems on your machine.
                However, care must be taken to  ensure  that
                you don't bounce mail that would be resolved
                correctly if  you  tried  again.   A  common
                strategy is to forward such mail to another,
                possibly better connected, mail server.

      -D        Perform no lookup in deferred delivery mode.
                This  flag  is  set  by default for the host
                map.

      -Sspacesub
                The character to use to replace space  char-
                acters  after  a successful map lookup (esp.
                useful for regex and syslog maps).

      -sspacesub
                For the dequote map only, the  character  to
                use  to  replace  space  characters  after a










Sendmail Installation and Operation Guide         SMM:08-129


                successful dequote.

      -q        Don't dequote the key before lookup.

      -Llevel   For the syslog map only,  it  specifies  the
                level to use for the syslog call.

      -A        When  rebuilding  an alias file, the -A flag
                causes duplicate entries in the text version
                to be merged.  For example, two entries:

                    list:user1, user2
                    list:user3

                would  be treated as though it were the sin-
                gle entry

                    list:user1, user2, user3

                in the presence of the -A flag.

           Some additional flags are available for the  host
      and dns maps:

      -d        delay: specify the resolver's retransmission
                time interval (in seconds).

      -r        retry:  specify  the  number  of  times   to
                retransmit a resolver query.

           The following additional flags are present in the
      ldap map only:

      -R        Do not auto chase referrals.  sendmail  must
                be  compiled  with  -DLDAP_REFERRALS  to use
                this flag.

      -n        Retrieve attribute names only.

      -Vsep     Retrieve both attributes name and  value(s),
                separated by sep.

      -rderef   Set  the  alias dereference option to one of
                never, always, search, or find.

      -sscope   Set search scope to one of  base,  one  (one
                level), or sub (subtree).

      -hhost    LDAP  server  hostname.  Some LDAP libraries
                allow you to specify  multiple,  space-sepa-
                rated  hosts  for  redundancy.  In addition,
                each of the hosts listed can be followed  by
                a  colon  and  a port number to override the










SMM:08-130         Sendmail Installation and Operation Guide


                default LDAP port.

      -bbase    LDAP search base.

      -pport    LDAP service port.

      -ltimelimit
                Time limit for LDAP queries.

      -Zsizelimit
                Size (number  of  matches)  limit  for  LDAP
                queries.

      -ddistinguished_name
                The  distinguished  name  to use to login to
                the LDAP server.

      -Mmethod  The  method  to  authenticate  to  the  LDAP
                server.   Should  be  one of LDAP_AUTH_NONE,
                LDAP_AUTH_SIMPLE, or LDAP_AUTH_KRBV4.

      -Ppasswordfile
                The file containing the secret key  for  the
                LDAP_AUTH_SIMPLE  authentication  method  or
                the name of the  Kerberos  ticket  file  for
                LDAP_AUTH_KRBV4.

      -1        Force  LDAP  searches  to  only succeed if a
                single match is found.  If  multiple  values
                are  found,  the  search is treated as if no
                match was found.

           The dbm map appends the strings ".pag" and ".dir"
      to  the given filename; the hash and btree maps append
      ".db".  For example, the map specification

          Kuucp dbm -o -N /etc/mail/uucpmap

      specifies an optional map named "uucp" of class "dbm";
      it  always  has null bytes at the end of every string,
      and      the      data       is       located       in
      /etc/mail/uucpmap.{dir,pag}.

           The  program  makemap(8) can be used to build any
      of the three database-oriented  maps.   It  takes  the
      following flags:

      -f        Do  not fold upper to lower case in the map.

      -N        Include null bytes in keys.

      -o        Append to an existing (old) file.











Sendmail Installation and Operation Guide         SMM:08-131


      -r        Allow replacement  of  existing  keys;  nor-
                mally,  re-inserting  an  existing key is an
                error.

      -v        Print what is happening.

      The sendmail daemon does not have to be  restarted  to
      read the new maps as long as you change them in place;
      file locking is used so that the maps  won't  be  read
      while they are being updated.

           New classes can be added in the routine setupmaps
      in file conf.c.

   5.10.  Q -- Queue Group Declaration

           In addition to the option  QueueDirectory,  queue
      groups  can be declared that define a (group of) queue
      directories under a common name.   The  syntax  is  as
      follows:

          Qname {, field=value}+

      where  name  is  the  symbolic name of the queue group
      under which it can be referenced in various places and
      the  "field=name" pairs define attributes of the queue
      group.  Fields are:

      Flags     Flags for this queue group.

      Nice      The nice(2) increment for the  queue  group.
                This value must be greater or equal zero.

      Interval  The time between two queue runs.

      Path      The queue directory of the group (required).

      Runners   The number of  parallel  runners  processing
                the  queue.   Note  that  F=f must be set if
                this value is greater than one.

      Jobs      The maximum number of jobs (messages  deliv-
                ered) per queue run.

      recipients
                The  maximum  number of recipients per enve-
                lope.  Envelopes with more than this  number
                of  recipients  will  be split into multiple
                envelopes in the same queue directory.   The
                default value 0 means no limit.

      Only the first character of the field name is checked.











SMM:08-132         Sendmail Installation and Operation Guide


           By default, a queue group named mqueue is defined
      that  uses  the  value of the QueueDirectory option as
      path.  Notice: all  paths  that  are  used  for  queue
      groups   must  be  subdirectories  of  QueueDirectory.
      Since they can be symbolic links, this  isn't  a  real
      restriction,  If  QueueDirectory uses a wildcard, then
      the directory one level up is considered the  ``base''
      directory  which  all  other  queue  directories  must
      share.  Please make sure that the queue directories do
      not overlap, e.g., do not specify

          O QueueDirectory=/var/spool/mqueue/*
          Qone, P=/var/spool/mqueue/dir1
          Qtwo, P=/var/spool/mqueue/dir2

      because  this  also  includes "dir1" and "dir2" in the
      default queue group.  However,

          O QueueDirectory=/var/spool/mqueue/main*
          Qone, P=/var/spool/mqueue/dir
          Qtwo, P=/var/spool/mqueue/other*

      is a valid queue group specification.

           Options listed in the ``Flags'' field can be used
      to  modify  the  behavior of a queue group.  The ``f''
      flag must be set if multiple queue  runners  are  sup-
      posed to work on the entries in a queue group.  Other-
      wise  sendmail  will  work  on  the  entries  strictly
      sequentially.

           The  ``Interval''  field  sets  the  time between
      queue runs.  If no queue group  specific  interval  is
      set, then the parameter of the -q option from the com-
      mand line is used.

           To control the  overall  number  of  concurrently
      active  queue  runners the option MaxQueueChildren can
      be set.  This limits the number of processes used  for
      running  the queues to MaxQueueChildren, though at any
      one time fewer processes may be active as a result  of
      queue options, completed queue runs, system load, etc.

           The maximum number of queue runners for an  indi-
      vidual  queue  group can be controlled via the Runners
      option.  If set to 0, entries in the queue will not be
      processed,  which  is  useful  to ``quarantine'' queue
      files.  The number of runners per queue group may also
      be  set  with  the  option  MaxRunnersPerQueue,  which
      applies to queue groups that have no individual limit.
      That  is,  the  default  value  for Runners is MaxRun-
      nersPerQueue if set, otherwise 1.











Sendmail Installation and Operation Guide         SMM:08-133


           The field Jobs describes the  maximum  number  of
      jobs  (messages delivered) per queue run, which is the
      queue group specific value of MaxQueueRunSize.

           Notice: queue groups should be declared after all
      queue  related  options  have  been  set because queue
      groups take their defaults from those options.  If  an
      option  is  set  after  a queue group declaration, the
      values of options in the queue group are  set  to  the
      defaults of sendmail unless explicitly set in the dec-
      laration.

           Each envelope is assigned to a queue group  based
      on  the  algorithm described in section ``Queue Groups
      and Queue Directories''.

   5.11.  X -- Mail Filter (Milter) Definitions

           The sendmail Mail Filter API (Milter) is designed
      to  allow third-party programs access to mail messages
      as they are being processed in order to  filter  meta-
      information  and  content.   They  are declared in the
      configuration file as:

          Xname {, field=value}*

      where name is the name of the filter (used  internally
      only)  and the "field=name" pairs define attributes of
      the filter.  Also see the documentation for the Input-
      MailFilters option for more information.

           Fields are:

          Socket    The socket specification
          Flags     Special flags for this filter
          Timeouts  Timeouts for this filter

      Only  the first character of the field name is checked
      (it's case-sensitive).

           The socket specification is one of the  following
      forms:

          S=inet: port @ host


          S=inet6: port @ host


          S=local: path

      The  first two describe an IPv4 or IPv6 socket listen-
      ing on a certain port at a given host or  IP  address.










SMM:08-134         Sendmail Installation and Operation Guide


      The  final  form  describes  a  named  socket  on  the
      filesystem at the given path.

           The following flags may  be  set  in  the  filter
      description.

      R   Reject connection if filter unavailable.

      T   Temporary fail connection if filter unavailable.

           If  neither F=R nor F=T is specified, the message
      is passed through sendmail in case of filter errors as
      if the failing filters were not present.

           The  timeouts  can  be  set using the four fields
      inside of the T= equate:

      C   Timeout for connecting to a filter.  If set to  0,
          the system's connect() timeout will be used.

      S   Timeout  for sending information from the MTA to a
          filter.

      R   Timeout for reading reply from the filter.

      E   Overall timeout between sending end-of-message  to
          filter and waiting for the final acknowledgment.

           Note  the separator between each timeout field is
      a  ';'.   The  default  values  (if  not   set)   are:
      T=C:5m;S:10s;R:10s;E:5m  where  s  is seconds and m is
      minutes.

           Examples:

          Xfilter1, S=local:/var/run/f1.sock, F=R
          Xfilter2, S=inet6:999@localhost, F=T, T=S:1s;R:1s;E:5m
          Xfilter3, S=inet:3333@localhost, T=C:2m


   5.12.  The User Database

           The user  database  is  deprecated  in  favor  of
      ``virtusertable''  and  ``genericstable'' as explained
      in the file cf/README.  If you have a version of send-
      mail  with  the user database package compiled in, the
      handling of sender and recipient  addresses  is  modi-
      fied.

           The  location of this database is controlled with
      the UserDatabaseSpec option.












Sendmail Installation and Operation Guide         SMM:08-135


      5.12.1.  Structure of the user database

              The database is a sorted (BTree-based)  struc-
         ture.  User records are stored with the key:

             user-name:field-name

         The   sorted  database  format  ensures  that  user
         records are clustered  together.   Meta-information
         is always stored with a leading colon.

              Field  names define both the syntax and seman-
         tics of the value.  Defined fields include:

         maildrop  The  delivery  address  for  this   user.
                   There  may  be  multiple  values  of this
                   record.   In  particular,  mailing  lists
                   will  have  one  maildrop record for each
                   user on the list.

         mailname  The outgoing mailname for this user.  For
                   each  outgoing  name,  there should be an
                   appropriate maildrop record for that name
                   to   allow   return   mail.    See   also
                   :default:mailname.

         mailsender
                   Changes any mail sent to this address  to
                   have the indicated envelope sender.  This
                   is intended for mailing lists,  and  will
                   normally  be  the  name of an appropriate
                   -request address.  It is very similar  to
                   the  owner-list syntax in the alias file.

         fullname  The full name of the user.

         office-address
                   The office address for this user.

         office-phone
                   The office phone number for this user.

         office-fax
                   The office FAX number for this user.

         home-address
                   The home address for this user.

         home-phone
                   The home phone number for this user.

         home-fax  The home FAX number for this user.











SMM:08-136         Sendmail Installation and Operation Guide


         project   A (short) description of the project this
                   person  is  affiliated with.  In the Uni-
                   versity this is often just  the  name  of
                   their graduate advisor.

         plan      A  pointer  to  a  file  from  which plan
                   information can be gathered.

              As of this writing, only a few of these fields
         are  actually  being used by sendmail: maildrop and
         mailname.  A finger program  that  uses  the  other
         fields is planned.

      5.12.2.  User database semantics

              When  the rewriting rules submit an address to
         the local mailer, the user name is  passed  through
         the  alias  file.   If no alias is found (or if the
         alias points back to the same  address),  the  name
         (with  ":maildrop"  appended) is then used as a key
         in the user database.  If no match  occurs  (or  if
         the  maildrop points at the same address), forward-
         ing is tried.

              If the first token of the user  name  returned
         by  ruleset  0  is  an  "@" sign, the user database
         lookup is skipped.  The intent  is  that  the  user
         database  will act as a set of defaults for a clus-
         ter (in our case, the Computer  Science  Division);
         mail sent to a specific machine should ignore these
         defaults.

              When mail is sent, the  name  of  the  sending
         user  is  looked  up in the database.  If that user
         has a "mailname" record, the value of  that  record
         is  used  as  their  outgoing name.  For example, I
         might have a record:

             eric:mailnameEric.Allman@CS.Berkeley.EDU

         This would cause my outgoing mail  to  be  sent  as
         Eric.Allman.

              If  a "maildrop" is found for the user, but no
         corresponding "mailname" record exists, the  record
         ":default:mailname" is consulted.  If present, this
         is the name of a host to override the  local  host.
         For  example,  in  our  case  we  would  set  it to
         "CS.Berkeley.EDU".  The effect is that anyone known
         in the database gets their outgoing mail stamped as
         "user@CS.Berkeley.EDU", but people  not  listed  in
         the database use the local hostname.











Sendmail Installation and Operation Guide         SMM:08-137


      5.12.3.  Creating the database[23]

              The user database is built from  a  text  file
         using  the  makemap utility (in the distribution in
         the makemap subdirectory).   The  text  file  is  a
         series  of  lines  corresponding to userdb records;
         each line has a key and a value separated by  white
         space.   The  key is always in the format described
         above -- for example:

             eric:maildrop

         This file is normally installed in a system  direc-
         tory;    for    example,   it   might   be   called
         /etc/mail/userdb.  To make the database version  of
         the map, run the program:

             makemap btree /etc/mail/userdb < /etc/mail/userdb

         Then  create  a  config  file  that uses this.  For
         example, using the V8 M4 configuration, include the
         following line in your .mc file:

             define(`confUSERDB_SPEC', /etc/mail/userdb)


6.  OTHER CONFIGURATION

        There  are  some  configuration  changes that can be
   made by recompiling  sendmail.   This  section  describes
   what  changes  can be made and what has to be modified to
   make them.  In most  cases  this  should  be  unnecessary
   unless you are porting sendmail to a new environment.

   6.1.  Parameters in devtools/OS/$oscf

           These  parameters  are  intended  to describe the
      compilation environment, not site policy,  and  should
      normally be defined in the operating system configura-
      tion file.  This section needs a complete rewrite.

      NDBM      If set, the new version of the  DBM  library
                that allows multiple databases will be used.
                If neither NDBM nor NEWDB are  set,  a  much
                less  efficient  method  of  alias lookup is
                used.
____________________
   [23]These instructions are known to be incomplete.  Other
features are available which provide similar  functionality,
e.g.,  virtual  hosting  and  mapping local addresses into a
generic form as explained in cf/README.












SMM:08-138         Sendmail Installation and Operation Guide


      NEWDB     If set, use the new  database  package  from
                Berkeley  (from  4.4BSD).   This  package is
                substantially faster than DBM or  NDBM.   If
                NEWDB  and  NDBM are both set, sendmail will
                read DBM files,  but  will  create  and  use
                NEWDB files.

      NIS       Include  support  for  NIS.  If set together
                with both NEWDB and NDBM, sendmail will cre-
                ate  both DBM and NEWDB files if and only if
                an alias file includes the substring  "/yp/"
                in  the name.  This is intended for compati-
                bility with Sun Microsystems'  mkalias  pro-
                gram used on YP masters.

      NISPLUS   Compile in support for NIS+.

      NETINFO   Compile  in  support  for NetInfo (NeXT sta-
                tions).

      LDAPMAP   Compile in support for  LDAP  X500  queries.
                Requires  libldap and liblber from the Umich
                LDAP  3.2  or  3.3  release  or   equivalent
                libraries  for  other LDAP libraries such as
                OpenLDAP.

      HESIOD    Compile in support for Hesiod.

      MAP_NSD   Compile in support for IRIX NSD lookups.

      MAP_REGEX Compile in support  for  regular  expression
                matching.

      DNSMAP    Compile  in  support  for DNS map lookups in
                the sendmail.cf file.

      PH_MAP    Compile in support for ph lookups.

      SASL      Compile in support for SASL, a required com-
                ponent for SMTP Authentication support.

      STARTTLS  Compile in support for STARTTLS.

      EGD       Compile  in support for the "Entropy Gather-
                ing Daemon" to provide  better  random  data
                for TLS.

      TCPWRAPPERS
                Compile in support for TCP Wrappers.

      _PATH_SENDMAILCF
                The pathname of the sendmail.cf file.











Sendmail Installation and Operation Guide         SMM:08-139


      _PATH_SENDMAILPID
                The pathname of the sendmail.pid file.

      SM_CONF_SHM
                Compile  in  support  for shared memory, see
                section about "/var/spool/mqueue".

      MILTER    Compile in support for  contacting  external
                mail filters built with the Milter API.

           There are also several compilation flags to indi-
      cate the environment such as "_AIX3" and "_SCO_unix_".
      See  the  sendmail/README file for the latest scoop on
      these flags.

   6.2.  Parameters in sendmail/conf.h

           Parameters and compilation options are defined in
      conf.h.   Most  of these need not normally be tweaked;
      common parameters are all  in  sendmail.cf.   However,
      the  sizes  of  certain  primitive  vectors, etc., are
      included in this  file.   The  numbers  following  the
      parameters are their default value.

           This  document is not the best source of informa-
      tion for compilation flags  in  conf.h  --  see  send-
      mail/README or sendmail/conf.h itself.

      MAXLINE [2048]
                  The maximum line length of any input line.
                  If message lines exceed this  length  they
                  will  still  be  processed correctly; how-
                  ever,  header  lines,  configuration  file
                  lines,  alias lines, etc., must fit within
                  this limit.

      MAXNAME [256]
                  The maximum length of any name, such as  a
                  host or a user name.

      MAXPV [256] The  maximum  number  of parameters to any
                  mailer.  This limits the number of recipi-
                  ents  that  may  be passed in one transac-
                  tion.  It can be set to any arbitrary num-
                  ber  above  about  10, since sendmail will
                  break up a delivery into  smaller  batches
                  as  needed.   A  higher  number may reduce
                  load on your system, however.

      MAXQUEUEGROUPS [50]
                  The maximum number of queue groups.












SMM:08-140         Sendmail Installation and Operation Guide


      MAXATOM [1000]
                  The maximum number of atoms (tokens) in  a
                  single  address.  For example, the address
                  "eric@CS.Berkeley.EDU" is seven atoms.

      MAXMAILERS [25]
                  The maximum number of mailers that may  be
                  defined  in  the configuration file.  This
                  value is defined in include/sendmail/send-
                  mail.h.

      MAXRWSETS [200]
                  The  maximum number of rewriting sets that
                  may be defined.  The first half  of  these
                  are  reserved  for  numeric  specification
                  (e.g., ``S92''), while the upper half  are
                  reserved    for    auto-numbering   (e.g.,
                  ``Sfoo'').  Thus, with a value of  200  an
                  attempt  to  use ``S99'' will succeed, but
                  ``S100'' will fail.

      MAXPRIORITIES [25]
                  The  maximum  number  of  values  for  the
                  "Precedence:"  field  that  may be defined
                  (using the P line in sendmail.cf).

      MAXUSERENVIRON [100]
                  The maximum number of items  in  the  user
                  environment  that will be passed to subor-
                  dinate mailers.

      MAXMXHOSTS [100]
                  The maximum number of MX records  we  will
                  accept for any single host.

      MAXMAPSTACK [12]
                  The  maximum  number  of  maps that may be
                  "stacked" in a sequence class map.

      MAXMIMEARGS [20]
                  The maximum number of arguments in a  MIME
                  Content-Type: header; additional arguments
                  will be ignored.

      MAXMIMENESTING [20]
                  The maximum depth to which  MIME  messages
                  may  be nested (that is, nested Message or
                  Multipart documents; this does  not  limit
                  the  number of components in a single Mul-
                  tipart document).

      MAXDAEMONS [10]
                  The maximum  number  of  sockets  sendmail










Sendmail Installation and Operation Guide         SMM:08-141


                  will  open  for  accepting  connections on
                  different ports.

      MAXMACNAMELEN [25]
                  The maximum length of a macro name.

      A number of other compilation  options  exist.   These
      specify  whether  or  not specific code should be com-
      piled in.  Ones marked with * are 0/1 valued.

      NETINET*    If set, support for Internet protocol net-
                  working is compiled in.  Previous versions
                  of sendmail referred to  this  as  DAEMON;
                  this old usage is now incorrect.  Defaults
                  on; turn it off in the  Makefile  if  your
                  system doesn't support the Internet proto-
                  cols.

      NETINET6*   If set, support  for  IPv6  networking  is
                  compiled   in.    It  must  be  separately
                  enabled by adding  DaemonPortOptions  set-
                  tings.

      NETISO*     If  set, support for ISO protocol network-
                  ing is compiled in (it may be  appropriate
                  to #define this in the Makefile instead of
                  conf.h).

      NETUNIX*    If set, support for UNIX domain sockets is
                  compiled  in.   This  is  used for control
                  socket support.

      LOG         If set, the syslog routine in use at  some
                  sites  is  used.   This  makes an informa-
                  tional log record for  each  message  pro-
                  cessed,  and  makes  a higher priority log
                  record   for   internal   system   errors.
                  STRONGLY  RECOMMENDED  --  if  you want no
                  logging, turn it off in the  configuration
                  file.

      MATCHGECOS* Compile  in  the code to do ``fuzzy match-
                  ing'' on the GECOS field  in  /etc/passwd.
                  This  also  requires  that  the MatchGECOS
                  option be turned on.

      NAMED_BIND* Compile in code to use the Berkeley Inter-
                  net  Name  Domain (BIND) server to resolve
                  TCP/IP host names.

      NOTUNIX     If you are using a non-UNIX  mail  format,
                  you  can set this flag to turn off special
                  processing of UNIX-style "From " lines.










SMM:08-142         Sendmail Installation and Operation Guide


      USERDB*     Include  the  experimental  Berkeley  user
                  information database package.  This adds a
                  new level of local name expansion  between
                  aliasing and forwarding.  It also uses the
                  NEWDB package.  This may change in  future
                  releases.

      The  following  options are normally turned on in per-
      operating-system clauses in conf.h.

      IDENTPROTO* Compile in the IDENT protocol  as  defined
                  in  RFC  1413.   This  defaults on for all
                  systems except  Ultrix,  which  apparently
                  has the interesting "feature" that when it
                  receives a "host unreachable"  message  it
                  closes  all open connections to that host.
                  Since some  firewall  gateways  send  this
                  error code when you access an unauthorized
                  port (such as 113, used by IDENT),  Ultrix
                  cannot receive email from such hosts.

      SYSTEM5     Set  all  of  the  compilation  parameters
                  appropriate for System V.

      HASFLOCK*   Use Berkeley-style flock instead of System
                  V  lockf  to  do file locking.  Due to the
                  highly unusual semantics of  locks  across
                  forks in lockf, this should always be used
                  if at all possible.

      HASINITGROUPS
                  Set this if  your  system  has  the  init-
                  groups()  call (if you have multiple group
                  support).  This is the default if  SYSTEM5
                  is not defined or if you are on HPUX.

      HASUNAME    Set  this  if you have the uname(2) system
                  call (or corresponding  library  routine).
                  Set by default if SYSTEM5 is set.

      HASGETDTABLESIZE
                  Set  this if you have the getdtablesize(2)
                  system call.

      HASWAITPID  Set this if  you  have  the  haswaitpid(2)
                  system call.

      FAST_PID_RECYCLE
                  Set this if your system can possibly reuse
                  the same pid in the same second of time.

      SFS_TYPE    The mechanism that can be used to get file
                  system  capacity  information.  The values










Sendmail Installation and Operation Guide         SMM:08-143


                  can be one of SFS_USTAT (use the  ustat(2)
                  syscall), SFS_4ARGS (use the four argument
                  statfs(2) syscall), SFS_VFS (use  the  two
                  argument   statfs(2)   syscall   including
                  <sys/vfs.h>), SFS_MOUNT (use the two argu-
                  ment     statfs(2)    syscall    including
                  <sys/mount.h>), SFS_STATFS  (use  the  two
                  argument   statfs(2)   syscall   including
                  <sys/statfs.h>), SFS_STATVFS (use the  two
                  argument   statfs(2)   syscall   including
                  <sys/statvfs.h>), or SFS_NONE (no  way  to
                  get this information).

      LA_TYPE     The   load   average  type.   Details  are
                  described below.

      The are several built-in ways of  computing  the  load
      average.   Sendmail tries to auto-configure them based
      on imperfect guesses; you can select one using the  cc
      option -DLA_TYPE=type, where type is:

      LA_INT      The  kernel stores the load average in the
                  kernel as an array of long integers.   The
                  actual  values  are  scaled  by  a  factor
                  FSCALE (default 256).

      LA_SHORT    The kernel stores the load average in  the
                  kernel as an array of short integers.  The
                  actual  values  are  scaled  by  a  factor
                  FSCALE (default 256).

      LA_FLOAT    The  kernel stores the load average in the
                  kernel as an  array  of  double  precision
                  floats.

      LA_MACH     Use MACH-style load averages.

      LA_SUBR     Call  the  getloadavg  routine  to get the
                  load average as an array of doubles.

      LA_ZERO     Always return zero as  the  load  average.
                  This is the fallback case.

      If  type  LA_INT,  LA_SHORT, or LA_FLOAT is specified,
      you may also need to specify _PATH_UNIX (the  path  to
      your  system  binary)  and LA_AVENRUN (the name of the
      variable containing the load average  in  the  kernel;
      usually "_avenrun" or "avenrun").

   6.3.  Configuration in sendmail/conf.c

           The following changes can be made in conf.c.











SMM:08-144         Sendmail Installation and Operation Guide


      6.3.1.  Built-in Header Semantics

              Not  all  header  semantics are defined in the
         configuration file.  Header lines that should  only
         be  included  by  certain mailers (as well as other
         more obscure semantics) must be  specified  in  the
         HdrInfo  table  in conf.c.  This table contains the
         header name (which should be in all lower case) and
         a  set  of  header control flags (described below),
         The flags are:

         H_ACHECK    Normally when the check is made to  see
                     if  a  header line is compatible with a
                     mailer, sendmail  will  not  delete  an
                     existing  line.   If  this flag is set,
                     sendmail  will  delete  even   existing
                     header  lines.  That is, if this bit is
                     set and the mailer does not  have  flag
                     bits   set   that  intersect  with  the
                     required mailer  flags  in  the  header
                     definition  in  sendmail.cf, the header
                     line is always deleted.

         H_EOH       If this header field is set,  treat  it
                     like a blank line, i.e., it will signal
                     the end of the header and the beginning
                     of the message text.

         H_FORCE     Add  this  header  entry  even  if  one
                     existed in the message  before.   If  a
                     header  entry  does  not  have this bit
                     set,  sendmail  will  not  add  another
                     header  line  if  a header line of this
                     name already existed.  This would  nor-
                     mally  be  used to stamp the message by
                     everyone who handled it.

         H_TRACE     If set, this  is  a  timestamp  (trace)
                     field.   If  the number of trace fields
                     in a message exceeds  a  preset  amount
                     the  message is returned on the assump-
                     tion that it has an aliasing loop.

         H_RCPT      If set, this field  contains  recipient
                     addresses.  This is used by the -t flag
                     to determine who to send to when it  is
                     collecting recipients from the message.

         H_FROM      This flag  indicates  that  this  field
                     specifies a sender.  The order of these
                     fields in the HdrInfo  table  specifies
                     sendmail's  preference  for which field
                     to return error messages to.










Sendmail Installation and Operation Guide         SMM:08-145


         H_ERRORSTO  Addresses in this header should receive
                     error messages.

         H_CTE       This   header  is  a  Content-Transfer-
                     Encoding header.

         H_CTYPE     This header is a Content-Type header.

         H_STRIPVAL  Strip the value from  the  header  (for
                     Bcc:).

         Let's look at a sample HdrInfo specification:

             struct hdrinfo                    HdrInfo[] =
             {
                      /* originator fields, most to least significant  */
                 "resent-sender",              H_FROM,
                 "resent-from",                H_FROM,
                 "sender",                     H_FROM,
                 "from",                       H_FROM,
                 "full-name",                  H_ACHECK,
                 "errors-to",                  H_FROM|H_ERRORSTO,
                      /* destination fields */
                 "to",                         H_RCPT,
                 "resent-to",                  H_RCPT,
                 "cc",                         H_RCPT,
                 "bcc",                        H_RCPT|H_STRIPVAL,
                      /* message identification and control */
                 "message",                    H_EOH,
                 "text",                       H_EOH,
                      /* trace fields */
                 "received",                   H_TRACE|H_FORCE,
                      /* miscellaneous fields */
                 "content-transfer-encoding",  H_CTE,
                 "content-type",               H_CTYPE,

                 NULL,                         0,
             };

         This  structure  indicates that the "To:", "Resent-
         To:",  and  "Cc:"  fields  all  specify   recipient
         addresses.   Any "Full-Name:" field will be deleted
         unless the required mailer flag (indicated  in  the
         configuration  file)  is specified.  The "Message:"
         and "Text:" fields will terminate the header; these
         are  used  by  random dissenters around the network
         world.  The "Received:" field will always be added,
         and can be used to trace messages.

              There  are  a number of important points here.
         First, header fields are  not  added  automatically
         just  because  they  are  in the HdrInfo structure;
         they must be specified in the configuration file in










SMM:08-146         Sendmail Installation and Operation Guide


         order  to  be  added  to  the  message.  Any header
         fields mentioned in the configuration file but  not
         mentioned  in  the  HdrInfo  structure have default
         processing  performed;  that  is,  they  are  added
         unless  they  were in the message already.  Second,
         the HdrInfo structure only specifies  cliched  pro-
         cessing; certain headers are processed specially by
         ad hoc code regardless of the status  specified  in
         HdrInfo.   For  example,  the "Sender:" and "From:"
         fields are always scanned on ARPANET mail to deter-
         mine the sender[24]; this is used  to  perform  the
         "return  to  sender"  function.   The  "From:"  and
         "Full-Name:" fields are used to determine the  full
         name  of  the sender if possible; this is stored in
         the macro $x and used in a number of ways.

      6.3.2.  Restricting Use of Email

              If it is necessary to restrict mail through  a
         relay,  the  checkcompat  routine  can be modified.
         This routine is called for every recipient address.
         It  returns an exit status indicating the status of
         the message.  The status EX_OK accepts the address,
         EX_TEMPFAIL queues the message for a later try, and
         other values (commonly EX_UNAVAILABLE)  reject  the
         message.  It is up to checkcompat to print an error
         message (using usrerr) if the message is  rejected.
         For example, checkcompat could read:



















____________________
   [24]Actually, this is no longer true in SMTP; this infor-
mation is contained in the envelope.  The older ARPANET pro-
tocols  did not completely distinguish envelope from header.












Sendmail Installation and Operation Guide         SMM:08-147


             int
             checkcompat(to, e)
                 register ADDRESS *to;
                 register ENVELOPE *e;
             {
                 register STAB *s;

                 s = stab("private", ST_MAILER, ST_FIND);
                 if (s != NULL && e->e_from.q_mailer != LocalMailer &&
                     to->q_mailer == s->s_mailer)
                 {
                     usrerr("No private net mail allowed through this machine");
                     return (EX_UNAVAILABLE);
                 }
                 if (MsgSize > 50000 && bitnset(M_LOCALMAILER, to->q_mailer))
                 {
                     usrerr("Message too large for non-local delivery");
                     e->e_flags |= EF_NORETURN;
                     return (EX_UNAVAILABLE);
                 }
                 return (EX_OK);
             }

         This would reject messages greater than 50000 bytes
         unless they were local.  The EF_NORETURN  flag  can
         be  set in e->e_flags to suppress the return of the
         actual body of the message  in  the  error  return.
         The  actual use of this routine is highly dependent
         on the implementation, and use should be limited.

      6.3.3.  New Database Map Classes

              New key maps can be added by creating a  class
         initialization  function  and  a  lookup  function.
         These are then added to the routine setupmaps.

              The initialization function is called as

             xxx_map_init(MAP *map, char *args)

         The map is an internal data structure.  The args is
         a  pointer to the portion of the configuration file
         line following the map class name; flags and  file-
         names  can  be  extracted from this line.  The ini-
         tialization function must return true  if  it  suc-
         cessfully opened the map, false otherwise.

              The lookup function is called as

             xxx_map_lookup(MAP *map, char buf[], char **av, int *statp)

         The  map  defines  the map internally.  The buf has
         the input key.  This may be  (and  often  is)  used










SMM:08-148         Sendmail Installation and Operation Guide


         destructively.   The  av  is  a  list  of arguments
         passed in from the rewrite line.  The lookup  func-
         tion  should return a pointer to the new value.  If
         the map lookup fails, *statp should be  set  to  an
         exit  status  code; in particular, it should be set
         to EX_TEMPFAIL if recovery is to  be  attempted  by
         the higher level code.

      6.3.4.  Queueing Function

              The routine shouldqueue is called to decide if
         a message should be  queued  or  processed  immedi-
         ately.   Typically this compares the message prior-
         ity to the current load average.  The default defi-
         nition is:

             bool
             shouldqueue(pri, ctime)
                 long pri;
                 time_t ctime;
             {
                 if (CurrentLA < QueueLA)
                     return false;
                 return (pri > (QueueFactor / (CurrentLA - QueueLA + 1)));
             }

         If  the  current load average (global variable Cur-
         rentLA,  which  is  set  before  this  function  is
         called) is less than the low threshold load average
         (option x, variable QueueLA),  shouldqueue  returns
         false  immediately  (that is, it should not queue).
         If  the  current  load  average  exceeds  the  high
         threshold   load   average   (option   X,  variable
         RefuseLA), shouldqueue  returns  true  immediately.
         Otherwise,  it  computes  the function based on the
         message  priority,  the  queue  factor  (option  q,
         global  variable  QueueFactor), and the current and
         threshold load averages.

              An implementation wishing to take  the  actual
         age  of  the  message into account can also use the
         ctime parameter, which is the time that the message
         was first submitted to sendmail.  Note that the pri
         parameter is already  weighted  by  the  number  of
         times  the  message  has  been tried (although this
         tends to lower the priority  of  the  message  with
         time);  the  expectation is that the ctime would be
         used as an "escape clause" to ensure that  messages
         are eventually processed.














Sendmail Installation and Operation Guide         SMM:08-149


      6.3.5.  Refusing Incoming SMTP Connections

              The function refuseconnections returns true if
         incoming SMTP connections should be  refused.   The
         current  implementation is based exclusively on the
         current load average and the  refuse  load  average
         option (option X, global variable RefuseLA):

             bool
             refuseconnections()
             {
                 return (RefuseLA > 0 && CurrentLA >= RefuseLA);
             }

         A  more  clever  implementation  could look at more
         system resources.

      6.3.6.  Load Average Computation

              The routine getla  returns  the  current  load
         average  (as  a rounded integer).  The distribution
         includes several possible implementations.  If  you
         are  porting  to  a new environment you may need to
         add some new tweaks.[25]

   6.4.  Configuration in sendmail/daemon.c

           The  file  sendmail/daemon.c contains a number of
      routines that are dependent on  the  local  networking
      environment.   The  version  supplied assumes you have
      BSD style sockets.

           In previous releases,  we  recommended  that  you
      modify the routine maphostname if you wanted to gener-
      alize $[ ... $] lookups.  We now  recommend  that  you
      create a new keyed map instead.

   6.5.  STARTTLS

           In  this section we assume that sendmail has been
      compiled  with  support  for  STARTTLS.   To  properly
      understand the use of STARTTLS in sendmail, it is nec-
      essary to understand at least some basics about  X.509
      certificates and public key cryptography.  This infor-
      mation can be found in books about SSL/TLS or  on  WWW
      sites, e.g., "http://www.OpenSSL.org/".


____________________
   [25]If you do,  please  send  updates  to  sendmail@Send-
mail.ORG.












SMM:08-150         Sendmail Installation and Operation Guide


      6.5.1.  Certificates for STARTTLS

              When  acting  as  a  server, sendmail requires
         X.509 certificates to support STARTTLS: one as cer-
         tificate  for the server (ServerCertFile and corre-
         sponding private ServerKeyFile) at least  one  root
         CA  (CACertFile),  i.e., a certificate that is used
         to sign other certificates, and a path to a  direc-
         tory  which  contains  other CAs (CACertPath).  The
         file specified via CACertFile can  contain  several
         certificates of CAs.  The DNs of these certificates
         are sent to the client during the TLS handshake (as
         part  of  the  CertificateRequest)  as  the list of
         acceptable CAs.  However, do not list too many root
         CAs  in  that file, otherwise the TLS handshake may
         fail; e.g.,

             error:14094417:SSL routines:SSL3_READ_BYTES:
             sslv3 alert illegal parameter:s3_pkt.c:964:SSL alert number 47

         You should probably put only the CA cert into  that
         file that signed your own cert(s), or at least only
         those you trust.   The  CACertPath  directory  must
         contain  the hashes of each CA certificate as file-
         names (or as links to them).  Symbolic links can be
         generated  with  the  following  two (Bourne) shell
         commands:

             C=FileName_of_CA_Certificate
             ln -s $C `openssl x509 -noout -hash < $C`.0

         An X.509 certificate is also required for authenti-
         cation  in  client  mode (ClientCertFile and corre-
         sponding private ClientKeyFile), however,  sendmail
         will  always use STARTTLS when offered by a server.
         The client and server certificates can  be  identi-
         cal.   Certificates can be obtained from a certifi-
         cate authority or created with the help of OpenSSL.
         The  required  format  for certificates and private
         keys is PEM.  To allow  for  automatic  startup  of
         sendmail,  private  keys (ServerKeyFile, ClientKey-
         File) must be stored  unencrypted.   The  keys  are
         only  protected by the permissions of the file sys-
         tem.  Never make a private key available to a third
         party.

      6.5.2.  Encoding of STARTTLS related Macros

              Macros  that  contain  STARTTLS  related  data
         which comes from outside sources, e.g., all  macros
         containing   information   from  certificates,  are
         encoded to avoid  problems  with  non-printable  or
         special  characters.  The latter are '<', '>', '(',










Sendmail Installation and Operation Guide         SMM:08-151


         ')', '"', '+', and ' '.  All  of  these  characters
         are  replaced  by their value in hexadecimal with a
         leading '+'.  For example:

             /C=US/ST=California/O=endmail.org/OU=private/CN=Darth Mail (Cert)/
             Email=darth+cert@endmail.org

         is encoded as:

             /C=US/ST=California/O=endmail.org/OU=private/
             CN=Darth+20Mail+20+28Cert+29/Email=darth+2Bcert@endmail.org

         (line breaks have been inserted  for  readability).
         The  macros  which are subject to this encoding are
         {cert_subject},  {cert_issuer},  {cn_subject},  and
         {cn_issuer}.

      6.5.3.  PRNG for STARTTLS

              STARTTLS  requires a strong pseudo random num-
         ber generator (PRNG) to operate properly.   Depend-
         ing  on the TLS library you use, it may be required
         to explicitly initialize the PRNG with random data.
         OpenSSL  makes  use of /dev/urandom(4) if available
         (this corresponds  to  the  compile  flag  HASURAN-
         DOMDEV).   On  systems  which  lack this support, a
         random file must be specified  in  the  sendmail.cf
         file  using  the  option  RandFile.  It is strongly
         advised to use the "Entropy Gathering  Daemon"  EGD
         from  Brian Warner on those systems to provide use-
         ful random data.  In this case,  sendmail  must  be
         compiled with the flag EGD, and the RandFile option
         must  point  to  the  EGD   socket.    If   neither
         /dev/urandom(4)  nor EGD are available, you have to
         make sure that useful random data is available  all
         the time in RandFile.  If the file hasn't been mod-
         ified in the last 10 minutes before it is  supposed
         to  be  used  by sendmail the content is considered
         obsolete.  One method for generating this file is:

             openssl rand -out /etc/mail/randfile -rand /path/to/file:...256

         See the OpenSSL documentation for more information.
         In  this case, the PRNG for TLS is only seeded with
         other random data if the  DontBlameSendmail  option
         InsufficientEntropy  is  set.   This is most likely
         not sufficient for certain actions,  e.g.,  genera-
         tion of (temporary) keys.

              Please  see the OpenSSL documentation or other
         sources for further information about certificates,
         their creation and their usage, the importance of a
         good PRNG, and other aspects of TLS.










SMM:08-152         Sendmail Installation and Operation Guide


7.  ACKNOWLEDGEMENTS

        I've worked on sendmail for  many  years,  and  many
   employers  have  been remarkably patient about letting me
   work on a large project that was not part of my  official
   job.   This  includes  time  on the INGRES Project at the
   University of California at Berkeley, at Britton Lee, and
   again on the Mammoth and Titan Projects at Berkeley.

        Much of the second wave of improvements resulting in
   version 8.1 should be credited to Bryan Costales  of  the
   International  Computer  Science Institute.  As he passed
   me drafts of his book on sendmail I was inspired to start
   working  on  things  again.   Bryan was also available to
   bounce ideas off of.

        Gregory Neil Shapiro of Worcester Polytechnic Insti-
   tute  has  become  instrumental in all phases of sendmail
   support and development, and was largely responsible  for
   getting versions 8.8 and 8.9 out the door.

        Many,  many  people  contributed  chunks of code and
   ideas to sendmail.  It has proven to be a  group  network
   effort.   Version  8  in  particular was a group project.
   The following people and organizations made notable  con-
   tributions:

       Claus Assmann
       John Beck, Hewlett-Packard & Sun Microsystems
       Keith Bostic, CSRG, University of California, Berkeley
       Andrew Cheng, Sun Microsystems
       Michael J. Corrigan, University of California, San Diego
       Bryan Costales, International Computer Science Institute & InfoBeat
       Par (Pell) Emanuelsson
       Craig Everhart, Transarc Corporation
       Per Hedeland, Ericsson
       Tom Ivar Helbekkmo, Norwegian School of Economics
       Kari Hurtta, Finnish Meteorological Institute
       Allan E. Johannesen, WPI
       Jonathan Kamens, OpenVision Technologies, Inc.
       Takahiro Kanbe, Fuji Xerox Information Systems Co., Ltd.
       Brian Kantor, University of California, San Diego
       John Kennedy, Cal State University, Chico
       Murray S. Kucherawy, HookUp Communication Corp.
       Bruce Lilly, Sony U.S.
       Karl London
       Motonori Nakamura, Ritsumeikan University & Kyoto University
       John Gardiner Myers, Carnegie Mellon University
       Neil Rickert, Northern Illinois University
       Gregory Neil Shapiro, WPI
       Eric Schnoebelen, Convex Computer Corp.
       Eric Wassenaar, National Institute for Nuclear and High Energy Physics, Amsterdam
       Randall Winchester, University of Maryland










Sendmail Installation and Operation Guide         SMM:08-153


       Christophe Wolfhugel, Pasteur Institute & Herve Schauer Consultants (Paris)
       Exactis.com, Inc.

   I apologize for anyone I have omitted, misspelled, misat-
   tributed, or otherwise missed.  At this point, I  suspect
   that at least a hundred people have contributed code, and
   many more have contributed ideas, comments,  and  encour-
   agement.  I've tried to list them in the RELEASE_NOTES in
   the distribution directory.  I appreciate their contribu-
   tion as well.

        Special thanks are reserved for Michael Corrigan and
   Christophe Wolfhugel, who besides being wonderful  guinea
   pigs  and contributors have also consented to be added to
   the ``sendmail@Sendmail.ORG'' list and, by answering  the
   bulk of the questions sent to that list, have freed me up
   to do other work.

















































                          APPENDIX  A


                      COMMAND LINE FLAGS




     Arguments  must  be   presented   with   flags   before
addresses.  The flags are:

-Ax       Select  an  alternative  .cf  file which is either
          sendmail.cf for -Am  or  submit.cf  for  -Ac.   By
          default the .cf file is chosen based on the opera-
          tion mode.  For -bm (default), -bs, and -t  it  is
          submit.cf if it exists, for all others it is send-
          mail.cf.

-bx       Set operation mode to x.  Operation modes are:

              m   Deliver mail (default)
              s   Speak SMTP on input side
              a*  ``Arpanet'' mode (get envelope sender information from header)
              d   Run as a daemon in background
              D   Run as a daemon in foreground
              t   Run in test mode
              v   Just verify addresses, don't collect or deliver
              i   Initialize the alias database
              p   Print the mail queue
              P   Print overview over the mail queue (requires shared memory)
              h   Print the persistent host status database
              H   Purge expired entries from the persistent host status database


-Btype    Indicate body type.

-Cfile    Use a different configuration file.  Sendmail runs
          as  the invoking user (rather than root) when this
          flag is specified.

-dlevel   Set debugging level.

-f addr   The envelope sender address is set to addr.   This
          address  may  also  be used in the From: header if
          that header is missing during initial  submission.
          The envelope sender address is used as the recipi-
          ent for delivery status notifications and may also
          appear in a Return-Path: header.

____________________
   *Deprecated.




SMM:08-154         Sendmail Installation and Operation Guide







Sendmail Installation and Operation Guide         SMM:08-155


-F name   Sets the full name of this user to name.

-G        When  accepting  messages  via  the  command line,
          indicate that they are for relay (gateway) submis-
          sion.   sendmail  may complain about syntactically
          invalid messages, e.g.,  unqualified  host  names,
          rather  than  fixing  them  when this flag is set.
          sendmail will not do any canonicalization in  this
          mode.

-h cnt    Sets  the "hop count" to cnt.  This represents the
          number of times this message has been processed by
          sendmail  (to  the  extent that it is supported by
          the underlying networks).  Cnt is incremented dur-
          ing  processing,  and  if  it reaches MAXHOP (cur-
          rently 25) sendmail throws away the  message  with
          an error.

-L tag    Sets  the  identifier  used for syslog.  Note that
          this identifier is set as early as possible.  How-
          ever,  sendmail  may  be  used  if  problems arise
          before the command line arguments are processed.

-n        Don't do aliasing or forwarding.

-N notifications
          Tag all addresses being sent as wanting the  indi-
          cated  notifications,  which  consists of the word
          "NEVER" or a comma-separated  list  of  "SUCCESS",
          "FAILURE",  and  "DELAY"  for successful delivery,
          failure, and a message that is stuck  in  a  queue
          somewhere.  The default is "FAILURE,DELAY".

-r addr   An obsolete form of -f.

-oxvalue  Set  option  x  to  the  specified  value.   These
          options are described in Section 5.6.

-Ooption=value
          Set option to the specified value (for  long  form
          option  names).   These  options  are described in
          Section 5.6.

-Mxvalue  Set macro x to the specified value.

-pprotocol
          Set the sending protocol.  Programs are encouraged
          to  set  this.   The  protocol field can be in the
          form protocol:host to set both the sending  proto-
          col and sending host.  For example, "-pUUCP:uunet"
          sets the sending protocol to UUCP and the  sending
          host to uunet.  (Some existing programs use -oM to
          set the r and s  macros;  this  is  equivalent  to










SMM:08-156         Sendmail Installation and Operation Guide


          using -p.)

-qtime    Try to process the queued up mail.  If the time is
          given, a sendmail will start one or more processes
          to  run through the queue(s) at the specified time
          interval to deliver  queued  mail;  otherwise,  it
          only runs once.  Each of these processes acts on a
          workgroup.  These  processes  are  also  known  as
          workgroup  processes  or  WGP's  for  short.  Each
          workgroup is responsible for controlling the  pro-
          cessing  of  one  or  more queues; workgroups help
          manage the use of system  resources  by  sendmail.
          Each  workgroup may have one or more children con-
          currently processing queues depending on the  set-
          ting of MaxQueueChildren.

-qptime   Similar  to  -q  with a time argument, except that
          instead of periodically  starting  WGP's  sendmail
          starts  persistent  WGP's  that  alternate between
          processing queues and sleeping.  The sleep time is
          specified  by  the time argument; it defaults to 1
          second, except that a WGP always sleeps at least 5
          seconds if their queues were empty in the previous
          run.  Persistent processes are managed by a  queue
          control  process  (QCP).   The  QCP  is the parent
          process of the WGP's.  Typically the QCP  will  be
          the sendmail daemon (when started with -bd or -bD)
          or a special process (named Queue  control)  (when
          started  without -bd or -bD).  If a persistent WGP
          ceases to be active for some  reason  another  WGP
          will  be started by the QCP for the same workgroup
          in most cases. When  a  persistent  WGP  has  core
          dumped,  the  debug  flag no_persistent_restart is
          set  or  the  specific  persistent  WGP  has  been
          restarted too many times already then the WGP will
          not be started again and a message will be  logged
          to  this  effect.   To  stop  (SIGTERM) or restart
          (SIGHUP) persistent WGP's the  appropriate  signal
          should  be sent to the QCP. The QCP will propagate
          the signal to all of the WGP's and if  appropriate
          restart the persistent WGP's.

-qGname   Run the jobs in the queue group name once.

-q[!]Xstring
          Run  the  queue  once,  limiting the jobs to those
          matching Xstring.  The key letter X can  be  I  to
          limit  based on queue identifier, R to limit based
          on recipient, or S to limit based  on  sender.   A
          particular  queued  job  is accepted if one of the
          corresponding  addresses  contains  the  indicated
          string.  The optional ! character negates the con-
          dition tested.  Multiple -qX flags are  permitted,










Sendmail Installation and Operation Guide         SMM:08-157


          with  items  with  the  same  key  letter  "or'ed"
          together, and items  with  different  key  letters
          "and'ed" together.

-R ret    What  information you want returned if the message
          bounces; ret can be "HDRS"  for  headers  only  or
          "FULL"  for  headers plus body.  This is a request
          only; the other end is not required to  honor  the
          parameter.   If  "HDRS" is specified local bounces
          also return only the headers.

-t        Read the  header  for  "To:",  "Cc:",  and  "Bcc:"
          lines, and send to everyone listed in those lists.
          The "Bcc:" line will be  deleted  before  sending.
          Any  addresses  in  the  argument  vector  will be
          deleted from the send list.

-V envid  The indicated envid is passed with the envelope of
          the message and returned if the message bounces.

-X logfile
          Log  all  traffic  in  and  out of sendmail in the
          indicated logfile for debugging  mailer  problems.
          This  produces  a  lot  of  data  very quickly and
          should be used sparingly.

     There are a number of options that may be specified  as
primitive  flags.   These  are  the  e, i, m, and v options.
Also, the f option may be specified as the -s flag.  The DSN
related  options  "-N",  "-R",  and  "-V" have no effects on
sendmail running as daemon.



































                        APPENDIX  B


                     QUEUE FILE FORMATS




     This appendix describes the format of the queue  files.
These  files  live in a queue directory.  The individual qf,
df, and xf files may be stored in separate qf/, df/, and xf/
subdirectories if they are present in the queue directory.

     All  queue  files  have  the name ttYMDhmsNNppppp where
YMDhmsNNppppp is the id for this message and  the  tt  is  a
type.  The individual letters in the id are:

Y    Encoded year

M    Encoded month

D    Encoded day

h    Encoded hour

m    Encoded minute

s    Encoded second

NN   Encoded envelope number

ppppp
     At least five decimal digits of the process ID

     All files with the same id collectively define one mes-
sage.  Due to the use  of  memory-buffered  files,  some  of
these files may never appear on disk.

     The types are:

qf   The  queue control file.  This file contains the infor-
     mation necessary to process the job.

df   The data file.  The message body (excluding the header)
     is  kept  in  this  file.  Sometimes the df file is not
     stored in the same directory as the qf  file;  in  this
     case, the qf file contains a `d' record which names the
     queue directory that contains the df file.

tf   A temporary file.  This is an image of the qf file when
     it is being rebuilt.  It should be renamed to a qf file
     very quickly.



SMM:08-158         Sendmail Installation and Operation Guide







Sendmail Installation and Operation Guide         SMM:08-159


xf   A transcript file, existing during the life of  a  ses-
     sion  showing  everything that happens during that ses-
     sion.  Sometimes the xf file must be generated before a
     queue  group  has  been  selected; in this case, the xf
     file will be stored in a directory of the default queue
     group.

Qf   A  ``lost''  queue control file.  sendmail renames a qf
     file to Qf if there is a severe (configuration) problem
     that  cannot  be  solved  without  human  intervention.
     Search the logfile for the queue file id to figure  out
     what happened.  After you resolved the problem, you can
     rename the Qf file to qf and send it again.

     The qf file is structured as a  series  of  lines  each
beginning with a code letter.  The lines are as follows:

V    The  version  number  of the queue file format, used to
     allow new sendmail binaries to read queue files created
     by  older versions.  Defaults to version zero.  Must be
     the first line of the file if present.   For  8.12  the
     version number is 6.

A    The  information  given  by  the AUTH= parameter of the
     "MAIL FROM:" command or  $f@$j  if  sendmail  has  been
     called directly.

H    A  header definition.  There may be any number of these
     lines.  The order  is  important:  they  represent  the
     order  in the final message.  These use the same syntax
     as header definitions in the configuration file.

C    The    controlling    address.     The    syntax     is
     "localuser:aliasname".   Recipient  addresses following
     this line will be flagged so that  deliveries  will  be
     run  as the localuser (a user name from the /etc/passwd
     file); aliasname is the name of the alias that expanded
     to this address (used for printing messages).

Q    The  ``original  recipient'',  specified  by the ORCPT=
     field in an ESMTP transaction.   Used  exclusively  for
     Delivery  Status Notifications.  It applies only to the
     following `R' line.

r    The ``final recipient'' used for Delivery Status  Noti-
     fications.   It applies only to the following `R' line.

R    A recipient address.  This will normally be  completely
     aliased, but is actually realiased when the job is pro-
     cessed.  There will be one  line  for  each  recipient.
     Version  1 qf files also include a leading colon-termi-
     nated list of flags, which can be `S' to return a  mes-
     sage  on  successful  final  delivery,  `F' to return a










SMM:08-160         Sendmail Installation and Operation Guide


     message on failure, `D' to return a message if the mes-
     sage  is  delayed, `B' to indicate that the body should
     be returned, `N' to suppress returning  the  body,  and
     `P'  to  declare this as a ``primary'' (command line or
     SMTP-session) address.

S    The sender address.  There may only  be  one  of  these
     lines.

T    The job creation time.  This is used to compute when to
     time out the job.

P    The current message priority.  This is  used  to  order
     the  queue.  Higher numbers mean lower priorities.  The
     priority changes as the message sits in the queue.  The
     initial  priority  depends on the message class and the
     size of the message.

M    A message.  This line is printed by the mailq  command,
     and  is generally used to store status information.  It
     can contain any text.

F    Flag bits, represented as one letter per flag.  Defined
     flag bits are r indicating that this is a response mes-
     sage and w indicating that a warning message  has  been
     sent  announcing that the mail has been delayed.  Other
     flag bits are: 8: the body contains  8bit  data,  b:  a
     Bcc:  header  should  be  removed,  d: the mail has RET
     parameters (see RFC 1894), n: the body of  the  message
     should  not  be  returned  in  case of an error, s: the
     envelope has been split.

N    The total number of delivery attempts.

K    The time (as seconds since January 1, 1970) of the last
     delivery attempt.

d    If  the df file is in a different directory than the qf
     file, then a `d'  record  is  present,  specifying  the
     directory in which the df file resides.

I    The  i-number  of  the  data  file; this can be used to
     recover your mail queue after a disastrous disk  crash.

$    A  macro  definition.  The values of certain macros are
     passed through to the queue run phase.

B    The body type.  The remainder of the  line  is  a  text
     string  defining the body type.  If this field is miss-
     ing, the body type is assumed to be "undefined" and  no
     special  processing  is  attempted.   Legal  values are
     "7BIT" and "8BITMIME".











Sendmail Installation and Operation Guide         SMM:08-161


Z    The original envelope id (from the ESMTP  transaction).
     For Deliver Status Notifications only.

     As  an  example,  the following is a queue file sent to
"eric@mammoth.Berkeley.EDU"  and   "bostic@okeeffe.CS.Berke-
ley.EDU"[1]:

    V4
    T711358135
    K904446490
    N0
    P2100941
    $_eric@localhost
    ${daemon_flags}
    Seric
    Ceric:100:1000:sendmail@vangogh.CS.Berkeley.EDU
    RPFD:eric@mammoth.Berkeley.EDU
    RPFD:bostic@okeeffe.CS.Berkeley.EDU
    H?P?Return-path: <^g>
    H??Received: by vangogh.CS.Berkeley.EDU (5.108/2.7) id AAA06703;
        Fri, 17 Jul 1992 00:28:55 -0700
    H??Received: from mail.CS.Berkeley.EDU by vangogh.CS.Berkeley.EDU (5.108/2.7)
        id AAA06698; Fri, 17 Jul 1992 00:28:54 -0700
    H??Received: from [128.32.31.21] by mail.CS.Berkeley.EDU (5.96/2.5)
        id AA22777; Fri, 17 Jul 1992 03:29:14 -0400
    H??Received: by foo.bar.baz.de (5.57/Ultrix3.0-C)
        id AA22757; Fri, 17 Jul 1992 09:31:25 GMT
    H?F?From: eric@foo.bar.baz.de (Eric Allman)
    H?x?Full-name: Eric Allman
    H??Message-id: <9207170931.AA22757@foo.bar.baz.de>
    H??To: sendmail@vangogh.CS.Berkeley.EDU
    H??Subject: this is an example message

This  shows  the person who sent the message, the submission
time (in seconds since January 1, 1970), the message  prior-
ity,  the message class, the recipients, and the headers for
the message.










____________________
   [1]This  example is contrived and probably inaccurate for
your environment.  Glance over it to get  an  idea;  nothing
can replace looking at what your own system generates.















                        APPENDIX  C


                  SUMMARY OF SUPPORT FILES




     This is a summary of the support  files  that  sendmail
creates or generates.  Many of these can be changed by edit-
ing the sendmail.cf file; check there  to  find  the  actual
pathnames.

/usr/sbin/sendmail
          The binary of sendmail.

/usr/bin/newaliases
          A  link  to  /usr/sbin/sendmail;  causes the alias
          database to be rebuilt.  Running this  program  is
          completely  equivalent  to giving sendmail the -bi
          flag.

/usr/bin/mailq
          Prints a listing of the mail queue.  This  program
          is equivalent to using the -bp flag to sendmail.

/etc/mail/sendmail.cf
          The configuration file, in textual form.

/etc/mail/helpfile
          The SMTP help file.

/etc/mail/statistics
          A statistics file; need not be present.

/etc/mail/sendmail.pid
          Created in daemon mode; it contains the process id
          of the current SMTP daemon.  If you  use  this  in
          scripts;  use  ``head  -1''  to get just the first
          line; the second line contains  the  command  line
          used  to  invoke the daemon, and later versions of
          sendmail may add more  information  to  subsequent
          lines.

/etc/mail/aliases
          The textual version of the alias file.

/etc/mail/aliases.db
          The alias file in hash(3) format.

/etc/mail/aliases.{pag,dir}
          The alias file in ndbm(3) format.



SMM:08-162         Sendmail Installation and Operation Guide







Sendmail Installation and Operation Guide         SMM:08-163


/var/spool/mqueue
          The  directory in which the mail queue(s) and tem-
          porary files reside.

/var/spool/mqueue/qf*
          Control (queue) files for messages.

/var/spool/mqueue/df*
          Data files.

/var/spool/mqueue/tf*
          Temporary versions of the qf  files,  used  during
          queue file rebuild.

/var/spool/mqueue/xf*
          A transcript of the current session.















































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Sendmail Installation and Operation Guide           SMM:08-3


                          TABLE OF CONTENTS

1.  BASIC INSTALLATION ................................    7
   1.1.  Compiling Sendmail ...........................    7
      1.1.1.  Tweaking the Build Invocation ...........    7
      1.1.2.  Creating a Site Configuration File ......    8
      1.1.3.  Tweaking the Makefile ...................    8
      1.1.4.  Compilation and installation ............    9
   1.2.  Configuration Files ..........................   10
   1.3.  Details of Installation Files ................   12
      1.3.1.  /usr/sbin/sendmail ......................   12
      1.3.2.  /etc/mail/sendmail.cf ...................   12
      1.3.3.  /etc/mail/submit.cf .....................   13
      1.3.4.  /usr/bin/newaliases .....................   13
      1.3.5.  /usr/bin/hoststat .......................   13
      1.3.6.  /usr/bin/purgestat ......................   13
      1.3.7.  /var/spool/mqueue .......................   14
      1.3.8.  /var/spool/clientmqueue .................   14
      1.3.9.  /var/spool/mqueue/.hoststat .............   15
      1.3.10.  /etc/mail/aliases* .....................   15
      1.3.11.  /etc/rc or /etc/init.d/sendmail ........   15
      1.3.12.  /etc/mail/helpfile .....................   16
      1.3.13.  /etc/mail/statistics ...................   16
      1.3.14.  /usr/bin/mailq .........................   16
      1.3.15.  sendmail.pid ...........................   18
      1.3.16.  Map Files ..............................   18
2.  NORMAL OPERATIONS .................................   18
   2.1.  The System Log ...............................   18
      2.1.1.  Format ..................................   18
      2.1.2.  Levels ..................................   20
   2.2.  Dumping State ................................   20
   2.3.  The Mail Queues ..............................   20
      2.3.1.  Queue Groups and Queue Directories ......   21
      2.3.2.  Queue Runs ..............................   22
      2.3.3.  Manual Intervention .....................   22
      2.3.4.  Printing the queue ......................   23
      2.3.5.  Forcing the queue .......................   23
   2.4.  Disk Based Connection Information ............   24
   2.5.  The Service Switch ...........................   26
   2.6.  The Alias Database ...........................   26
      2.6.1.  Rebuilding the alias database ...........   28
      2.6.2.  Potential problems ......................   29
      2.6.3.  List owners .............................   29
   2.7.  User Information Database ....................   30
   2.8.  Per-User Forwarding (.forward Files) .........   30
   2.9.  Special Header Lines .........................   30
      2.9.1.  Errors-To: ..............................   31
      2.9.2.  Apparently-To: ..........................   31
      2.9.3.  Precedence ..............................   31
   2.10.  IDENT Protocol Support ......................   31
3.  ARGUMENTS .........................................   32
   3.1.  Queue Interval ...............................   33
   3.2.  Daemon Mode ..................................   33










SMM:08-4           Sendmail Installation and Operation Guide


   3.3.  Forcing the Queue ............................   33
   3.4.  Debugging ....................................   34
   3.5.  Changing the Values of Options ...............   35
   3.6.  Trying a Different Configuration File ........   36
   3.7.  Logging Traffic ..............................   36
   3.8.  Testing Configuration Files ..................   36
   3.9.  Persistent Host Status Information ...........   38
4.  TUNING ............................................   39
   4.1.  Timeouts .....................................   39
      4.1.1.  Queue interval ..........................   39
      4.1.2.  Read timeouts ...........................   40
      4.1.3.  Message timeouts ........................   43
   4.2.  Forking During Queue Runs ....................   44
   4.3.  Queue Priorities .............................   44
   4.4.  Load Limiting ................................   45
   4.5.  Resource Limits ..............................   45
   4.6.  Delivery Mode ................................   46
   4.7.  Log Level ....................................   46
   4.8.  File Modes ...................................   48
      4.8.1.  To suid or not to suid?  ................   48
      4.8.2.  Turning off security checks .............   49
   4.9.  Connection Caching ...........................   52
   4.10.  Name Server Access ..........................   53
   4.11.  Moving the Per-User Forward Files ...........   54
   4.12.  Free Space ..................................   55
   4.13.  Maximum Message Size ........................   55
   4.14.  Privacy Flags ...............................   56
   4.15.  Send to Me Too ..............................   56
5.  THE WHOLE SCOOP ON THE CONFIGURATION FILE .........   56
   5.1.  R and S -- Rewriting Rules ...................   57
      5.1.1.  The left hand side ......................   57
      5.1.2.  The right hand side .....................   58
      5.1.3.  Semantics of rewriting rule sets ........   60
      5.1.4.  Ruleset hooks ...........................   62
         5.1.4.1.  check_relay ........................   62
         5.1.4.2.  check_mail .........................   62
         5.1.4.3.  check_rcpt .........................   62
         5.1.4.4.  check_data .........................   62
         5.1.4.5.  check_compat .......................   63
         5.1.4.6.  check_eoh ..........................   63
         5.1.4.7.  check_etrn .........................   64
         5.1.4.8.  check_expn .........................   64
         5.1.4.9.  check_vrfy .........................   64
         5.1.4.10.  trust_auth ........................   64
         5.1.4.11.  tls_client ........................   64
         5.1.4.12.  tls_server ........................   64
         5.1.4.13.  tls_rcpt ..........................   65
         5.1.4.14.  srv_features ......................   65
         5.1.4.15.  try_tls ...........................   65
         5.1.4.16.  authinfo ..........................   66
         5.1.4.17.  queuegroup ........................   66
      5.1.5.  IPC mailers .............................   66
   5.2.  D -- Define Macro ............................   67










Sendmail Installation and Operation Guide           SMM:08-5


   5.3.  C and F -- Define Classes ....................   77
   5.4.  M -- Define Mailer ...........................   80
   5.5.  H -- Define Header ...........................   88
   5.6.  O -- Set Option ..............................   89
   5.7.  P -- Precedence Definitions ..................  118
   5.8.  V -- Configuration Version Level .............  119
   5.9.  K -- Key File Declaration ....................  121
   5.10.  Q -- Queue Group Declaration ................  131
   5.11.  X -- Mail Filter (Milter) Definitions .......  133
   5.12.  The User Database ...........................  134
      5.12.1.  Structure of the user database .........  135
      5.12.2.  User database semantics ................  136
      5.12.3.  Creating the database[23] ..............  137
6.  OTHER CONFIGURATION ...............................  137
   6.1.  Parameters in devtools/OS/$oscf ..............  137
   6.2.  Parameters in sendmail/conf.h ................  139
   6.3.  Configuration in sendmail/conf.c .............  143
      6.3.1.  Built-in Header Semantics ...............  144
      6.3.2.  Restricting Use of Email ................  146
      6.3.3.  New Database Map Classes ................  147
      6.3.4.  Queueing Function .......................  148
      6.3.5.  Refusing Incoming SMTP Connections ......  149
      6.3.6.  Load Average Computation ................  149
   6.4.  Configuration in sendmail/daemon.c ...........  149
   6.5.  STARTTLS .....................................  149
      6.5.1.  Certificates for STARTTLS ...............  150
      6.5.2.  Encoding of  STARTTLS  related  Macros
         ..............................................  150
      6.5.3.  PRNG for STARTTLS .......................  151
7.  ACKNOWLEDGEMENTS ..................................  152
Appendix A.  COMMAND LINE FLAGS .......................  154
Appendix B.  QUEUE FILE FORMATS .......................  158
Appendix C.  SUMMARY OF SUPPORT FILES .................  162






























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