    ACCESS(5)                                               ACCESS(5)

    NAME
           access - format of Postfix access table

    SYNOPSIS
           postmap /usr/local/etc/postfix/access

           postmap -q "string" /usr/local/etc/postfix/access

           postmap -q - /usr/local/etc/postfix/access <inputfile

    DESCRIPTION
           The  optional access table directs the Postfix SMTP server
           to selectively  reject  or  accept  mail.  Access  can  be
           allowed  or  denied for specific host names, domain names,
           networks, host network addresses or mail addresses.

           For an example, see the EXAMPLE section at the end of this
           manual page.

           Normally,  the  access  table  is specified as a text file
           that serves as  input  to  the  postmap(1)  command.   The
           result,  an  indexed file in dbm or db format, is used for
           fast searching by the mail  system.  Execute  the  command
           postmap   /usr/local/etc/postfix/access  in  order  to  rebuild  the
           indexed file after changing the access table.

           When the table is provided via other means  such  as  NIS,
           LDAP  or  SQL,  the  same lookups are done as for ordinary
           indexed files.

           Alternatively, the table can be  provided  as  a  regular-
           expression map where patterns are given as regular expres-
           sions, or lookups can be directed to TCP-based server.  In
           that  case,  the  lookups are done in a slightly different
           way as described below under "REGULAR  EXPRESSION  TABLES"
           and "TCP-BASED TABLES".

    TABLE FORMAT
           The input format for the postmap(1) command is as follows:

           pattern action
                  When pattern matches a mail address, domain or host
                  address, perform the corresponding action.

           blank lines and comments
                  Empty  lines and whitespace-only lines are ignored,
                  as are lines whose first  non-whitespace  character
                  is a `#'.

           multi-line text
                  A  logical  line starts with non-whitespace text. A
                  line that starts with whitespace continues a  logi-
                  cal line.

    EMAIL ADDRESS PATTERNS
           With lookups from indexed files such as DB or DBM, or from
           networked tables such as NIS, LDAP or  SQL,  patterns  are
           tried in the order as listed below:

           user@domain
                  Matches the specified mail address.

           domain.tld
                  Matches  domain.tld  as the domain part of an email
                  address.

                  The pattern domain.tld also matches subdomains, but
                  only when the string smtpd_access_maps is listed in
                  the Postfix  parent_domain_matches_subdomains  con-
                  figuration  setting  (note that this is the default
                  for some versions of Postfix).  Otherwise,  specify
                  .domain.tld  (note  the  initial  dot)  in order to
                  match subdomains.

           user@  Matches all mail addresses with the specified  user
                  part.

           Note:  lookup  of  the null sender address is not possible
           with some types of lookup table. By default, Postfix  uses
           <>  as  the  lookup  key  for such addresses. The value is
           specified with the smtpd_null_access_lookup_key  parameter
           in the Postfix main.cf file.

    EMAIL ADDRESS EXTENSION
           When a mail address localpart contains the optional recip-
           ient delimiter (e.g., user+foo@domain), the  lookup  order
           becomes:  user+foo@domain, user@domain, domain, user+foo@,
           and user@.

    HOST NAME/ADDRESS PATTERNS
           With lookups from indexed files such as DB or DBM, or from
           networked  tables  such as NIS, LDAP or SQL, the following
           lookup patterns are examined in the order as listed:

           domain.tld
                  Matches domain.tld.

                  The pattern domain.tld also matches subdomains, but
                  only when the string smtpd_access_maps is listed in
                  the Postfix  parent_domain_matches_subdomains  con-
                  figuration setting.  Otherwise, specify .domain.tld
                  (note the initial dot) in  order  to  match  subdo-
                  mains.

           net.work.addr.ess

           net.work.addr

           net.work

           net    Matches  any host address in the specified network.
                  A network address is a  sequence  of  one  or  more
                  octets separated by ".".

                  NOTE:  use  the  cidr  lookup table type to specify
                  network/netmask  patterns.  See  cidr_table(5)  for
                  details.

    ACCEPT ACTIONS
           OK     Accept the address etc. that matches the pattern.

           all-numerical
                  An all-numerical result is treated as OK. This for-
                  mat is generated by address-based relay  authoriza-
                  tion schemes.

    REJECT ACTIONS
           4NN text

           5NN text
                  Reject  the  address etc. that matches the pattern,
                  and respond with the numerical three-digit code and
                  text.  4NN means "try again later", while 5NN means
                  "do not try again".

           REJECT optional text...
                  Reject the address etc. that matches  the  pattern.
                  Reply  with  $reject_code optional text... when the
                  optional text is specified, otherwise reply with  a
                  generic error response message.

           DEFER_IF_REJECT optional text...
                  Defer  the  request if some later restriction would
                  result in a REJECT action. Reply with "450 optional
                  text... when the optional text is specified, other-
                  wise reply with a generic error response message.

                  This feature is available in Postfix 2.1 and later.

           DEFER_IF_PERMIT optional text...
                  Defer  the  request if some later restriction would
                  result in a an explicit or implicit PERMIT  action.
                  Reply  with "450 optional text... when the optional
                  text is specified, otherwise reply with  a  generic
                  error response message.

                  This feature is available in Postfix 2.1 and later.

    OTHER ACTIONS
           restriction...
                  Apply the named UCE restriction(s) (permit, reject,
                  reject_unauth_destination, and so on).

           DISCARD optional text...
                  Claim  successful delivery and silently discard the
                  message.  Log the optional text if specified,  oth-
                  erwise log a generic message.

                  Note:  this action currently affects all recipients
                  of the message.

                  This feature is available in Postfix 2.0 and later.

           DUNNO  Pretend  that  the  lookup  key was not found. This
                  prevents Postfix  from  trying  substrings  of  the
                  lookup  key (such as a subdomain name, or a network
                  address subnetwork).

                  This feature is available in Postfix 2.0 and later.

           FILTER transport:destination
                  After  the  message is queued, send the entire mes-
                  sage through the specified external content filter.
                  The  transport:destination  syntax  is described in
                  the transport(5)  manual  page.   More  information
                  about  external  content  filters is in the Postfix
                  FILTER_README file.

                  Note:  this  action  overrides  the  main.cf   con-
                  tent_filter  setting,  and  currently  affects  all
                  recipients of the message.

                  This feature is available in Postfix 2.0 and later.

           HOLD optional text...
                  Place  the message on the hold queue, where it will
                  sit until someone either deletes it or releases  it
                  for  delivery.  Log the optional text if specified,
                  otherwise log a generic message.

                  Mail that is placed on hold can  be  examined  with
                  the  postcat(1)  command,  and  can be destroyed or
                  released with the postsuper(1) command.

                  Note: this action currently affects all  recipients
                  of the message.

                  This feature is available in Postfix 2.0 and later.

           PREPEND headername: headervalue
                  Prepend the specified message header  to  the  mes-
                  sage.  When this action is used multiple times, the
                  first prepended header appears  before  the  second
                  etc. prepended header.

                  Note:  this action does not support multi-line mes-
                  sage headers.

                  This feature is available in Postfix 2.1 and later.

           REDIRECT user@domain
                  After  the  message  is queued, send the message to
                  the  specified  address  instead  of  the  intended
                  recipient(s).

                  Note:  this action overrides the FILTER action, and
                  currently affects all recipients of the message.

                  This feature is available in Postfix 2.1 and later.

           WARN optional text...
                  Log a warning with the optional text, together with
                  client information and  if  available,  with  helo,
                  sender, recipient and protocol information.

                  This feature is available in Postfix 2.1 and later.

    REGULAR EXPRESSION TABLES
           This section describes how the table lookups  change  when
           the table is given in the form of regular expressions. For
           a description of regular expression lookup  table  syntax,
           see regexp_table(5) or pcre_table(5).

           Each  pattern  is  a regular expression that is applied to
           the entire string being looked up. Depending on the appli-
           cation,  that  string  is  an  entire  client hostname, an
           entire client IP address, or an entire mail address. Thus,
           no  parent  domain  or  parent  network  search  is  done,
           user@domain mail addresses are not broken  up  into  their
           user@ and domain constituent parts, nor is user+foo broken
           up into user and foo.

           Patterns are applied in the  order  as  specified  in  the
           table,  until  a  pattern is found that matches the search
           string.

           Actions are the same as with indexed  file  lookups,  with
           the  additional feature that parenthesized substrings from
           the pattern can be interpolated as $1, $2 and so on.

    TCP-BASED TABLES
           This section describes how the table lookups  change  when
           lookups are directed to a TCP-based server. For a descrip-
           tion  of  the  TCP  client/server  lookup  protocol,   see
           tcp_table(5).   This  feature  is not available in Postfix
           version 2.1.

           Each lookup operation uses the entire query  string  once.
           Depending  on  the  application,  that string is an entire
           client hostname, an entire client IP address, or an entire
           mail  address.   Thus,  no parent domain or parent network
           search is done, user@domain mail addresses are not  broken
           up  into  their user@ and domain constituent parts, nor is
           user+foo broken up into user and foo.

           Actions are the same as with indexed file lookups.

    EXAMPLE
           The following example uses an indexed file,  so  that  the
           order  of  table entries does not matter. The example per-
           mits access by the client at address 1.2.3.4  but  rejects
           all  other clients in 1.2.3.0/24. Instead of "hash" lookup
           tables, some systems use "dbm".  Use the command "postconf
           -m"  to  find  out  what lookup tables Postfix supports on
           your system.

           /usr/local/etc/postfix/main.cf:
               smtpd_client_restrictions =
                   check_client_access hash:/usr/local/etc/postfix/access

           /usr/local/etc/postfix/access:
               1.2.3   REJECT
               1.2.3.4 OK

           Execute the command "postmap /usr/local/etc/postfix/access" after
           editing the file.

    BUGS
           The table format does not understand quoting  conventions.

    SEE ALSO
           postmap(1), Postfix lookup table manager
           smtpd(8), SMTP server
           postconf(5), configuration parameters
           transport(5), transport:nexthop syntax

    README FILES
           SMTPD_ACCESS_README, built-in SMTP server access control
           DATABASE_README, Postfix lookup table overview

    LICENSE
           The Secure Mailer license must be  distributed  with  this
           software.

    AUTHOR(S)
           Wietse Venema
           IBM T.J. Watson Research
           P.O. Box 704
           Yorktown Heights, NY 10598, USA

                                                            ACCESS(5)