TRANSPORT(5)                                         TRANSPORT(5)

NAME
       transport - format of Postfix transport table

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

DESCRIPTION
       The  optional  transport  table  specifies  a mapping from
       domain hierarchies 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 below.

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.

       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:

       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:  transport  map entries take precedence over domains
       specified in the mydestination parameter. If you  use  the
       optional  transport  map,  it  may  be  safer  to  specify
       explicit entries for all domains specified  in  mydestina-
       tion, for example:

            hostname.my.domain   local:
            localhost.my.domain      local:

       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.

EXAMPLES
       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, the default  transport  is
       used, as specified via the default_transport configuration
       parameter. The following 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:

       default_transport
              The  transport  to use when no transport is explic-
              itly specified.

       relayhost
              The default host to send to when no transport table
              entry matches.

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)