    TRANSPORT(5)                                         TRANSPORT(5)

    NAME
           transport - format of Postfix transport table

    SYNOPSIS
           postmap /usr/local/etc/postfix/transport

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

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

    DESCRIPTION
           The  optional  transport  table  specifies  a mapping from
           email addresses  to  message  delivery  transports  and/or
           relay hosts. The mapping is used by the trivial-rewrite(8)
           daemon.

           Normally, the transport 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/transport in  order  to  rebuild  the
           indexed file after changing the transport 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.  In  that  case, the lookups are done in a slightly
           different way as described in the section titled  "REGULAR
           EXPRESSION TABLES".

    TABLE FORMAT
           The format of the transport table is as follows:

           pattern result
                  When  pattern  matches  the  domain, use the corre-
                  sponding result.

           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.

           In an indexed file, a pattern of `*' matches everything.

           The result is of the form transport:nexthop.   The  trans-
           port  field  specifies  a  mail delivery transport such as
           smtp or local. The nexthop field specifies where  and  how
           to  deliver  mail. A null transport or nexthop field means
           "do not change": use the delivery  transport  and  nexthop
           information that would be used if no match were found.

           The  interpretation  of  the  nexthop  field  is transport
           dependent. In the case of SMTP, specify host:service for a
           non-default  server port, and use [host] or [host]:port in
           order to disable MX (mail exchanger) DNS lookups.  The  []
           form  can  also be used with IP addresses instead of host-
           names.

           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+extension@domain transport:nexthop
                  Mail for user+extension@domain is delivered through
                  transport to nexthop.

           user@domain transport:nexthop
                  Mail for user@domain is delivered through transport
                  to nexthop.

           domain transport:nexthop
                  Mail for domain is delivered through  transport  to
                  nexthop.

           .domain transport:nexthop
                  Mail  for  any  subdomain  of  domain  is delivered
                  through transport to  nexthop.  This  applies  only
                  when the string transport_maps is not listed in the
                  parent_domain_matches_subdomains configuration set-
                  ting.   Otherwise, a domain name matches itself and
                  its subdomains.

    NOTE
           The special pattern <> represents the  null  address,  and
           the  special  pattern  *  represents  any address (i.e. it
           functions as the wild-card pattern).

    EXAMPLES
           In order to deliver internal mail directly, while using  a
           mail  relay  for  all other mail, specify a null entry for
           internal destinations (do not change the  delivery  trans-
           port  or  the  nexthop information) and specify a wildcard
           for all other destinations. Note that for  this  trick  to
           work  you  should  not  specify a relayhost in the main.cf
           file.

                my.domain    :
                .my.domain   :
                *            smtp:outbound-relay.my.domain

           In order to send mail for foo.org and its  subdomains  via
           the uucp transport to the UUCP host named foo:

                foo.org      uucp:foo
                .foo.org     uucp:foo

           When  no  nexthop  host name is specified, the destination
           domain name is used instead. For  example,  the  following
           directs  mail for user@foo.org via the slow transport to a
           mail exchanger for foo.org.  The slow transport  could  be
           something  that  runs  at  most  one delivery process at a
           time:

                foo.org      slow:

           When  no  transport  is  specified,  Postfix  uses  either
           $local_transport   or   $default_transport,  depending  on
           whether the destination matches $mydestination.  The  fol-
           lowing  sends  all  mail for foo.org and its subdomains to
           host gateway.foo.org:

                foo.org      :[gateway.foo.org]
                .foo.org     :[gateway.foo.org]

           In the above example, the  []  are  used  to  suppress  MX
           lookups.   The  result  would  likely  point to your local
           machine.

           In the case of delivery via SMTP, one  may  specify  host-
           name:service instead of just a host:

                foo.org      smtp:bar.org:2025

           This  directs  mail  for user@foo.org to host bar.org port
           2025. Instead of a numerical port a symbolic name  may  be
           used.  Specify  [] around the hostname in order to disable
           MX lookups.

           The error mailer can be used to bounce mail:

                .foo.org      error:mail for *.foo.org is not  deliv-
           erable

           This  causes  all  mail  for  user@anything.foo.org  to be
           bounced.

    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 domain being looked up. Thus, some.domain.hier-
           archy is not broken up into parent domains.

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

           Results  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.

    CONFIGURATION PARAMETERS
           The  following  main.cf parameters are especially relevant
           to this topic. See the Postfix  main.cf  file  for  syntax
           details  and  for  default  values. Use the postfix reload
           command after a configuration change.

           parent_domain_matches_subdomains
                  List of Postfix features that use  domain.tld  pat-
                  terns   to  match  sub.domain.tld  (as  opposed  to
                  requiring .domain.tld patterns).

           transport_maps
                  List of transport lookup tables.

           Other parameters of interest:

           local_transport
                  The mail delivery transport to use when  no  trans-
                  port  is  explicitly specified, and the destination
                  matches $mydestination.

           default_transport
                  The mail delivery transport to use when  no  trans-
                  port  is  explicitly specified, and the destination
                  does not match $mydestination.

           mydestination
                  The destinations that are given to $local_transport
                  by default.

           relayhost
                  The default host for destinations that do not match
                  $mydestination.

    SEE ALSO
           postmap(1) create mapping table
           trivial-rewrite(8) rewrite and resolve addresses
           pcre_table(5) format of PCRE tables
           regexp_table(5) format of POSIX regular expression tables

    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

                                                         TRANSPORT(5)