TRANSPORT(5)                                         TRANSPORT(5)


NAME
       transport - format of Postfix transport table

SYNOPSIS
       postmap /etc/postfix/transport

DESCRIPTION
       The  optional  transport  file  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 file serves as input to the postmap(1)  com-
       mand.  The result, an indexed file in dbm or db format, is
       used for fast searching by the mail  system.  Execute  the
       command postmap /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:

       blanks and comments
              Blank  lines  are  ignored,  as are lines beginning
              with `#'.

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

       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.

       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



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TRANSPORT(5)                                         TRANSPORT(5)


       mydestination, 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
       hostname: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 destination in order to disable MX lookups.

       The error mailer can be used to bounce mail:

            .foo.org      error:mail for *.foo.org is not deliverable

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




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TRANSPORT(5)                                         TRANSPORT(5)


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 normal 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.

       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





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