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TRANSPORT(5)                  File Formats Manual                 TRANSPORT(5)

       transport - format of Postfix transport table

       postmap /etc/postfix/transport

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

       postmap -q - /etc/postfix/transport <&lt;inputfile

       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.

       This mapping overrides the default routing that is built into Postfix:

              A list of domains that is by default delivered via $local_trans-

              A list of  domains  that  is  by  default  delivered  via  $vir-

              A list of domains that is by default delivered via $relay_trans-

       any other destination
              Mail for any other  destination  is  by  default  delivered  via

       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 /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 expressions. In that case, the
       lookups are done in a slightly different way as  described  in  section

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

       pattern result
              When  pattern  matches  the recipient address or domain, use the
              corresponding 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 logical line.

       The pattern specifies an email address, a domain name, or a domain name
       hierarchy, as described in section "TABLE LOOKUP".

       The result is of the form transport:nexthop.  The transport field spec-
       ifies a mail delivery transport such as  smtp  or  local.  The  nexthop
       field  specifies  where and how to deliver mail. More details are given
       in section "RESULT FORMAT".

       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

       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
              setting.  Otherwise, a domain name matches itself and its subdo-

       Note 1: the special pattern * represents any address (i.e. it functions
       as the wild-card pattern).

       Note   2:   the   null   recipient   address   is    looked    up    as
       $empty_address_recipient@$myhostname (default: mailer-daemon@hostname).

       The  transport  field  specifies  the name of a mail delivery transport
       (the first name of a mail delivery service entry in  the  Postfix  mas-
       ter.cf file).

       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 is required when you specify an IP address instead
       of a hostname.

       A null transport and null nexthop result means "do not change": use the
       delivery transport and nexthop information that would be used when  the
       entire transport table did not exist.

       A non-null transport field with a null nexthop field resets the nexthop
       information to the recipient domain.

       A null transport field with non-null nexthop field does not modify  the
       transport information.

       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 transport or the nexthop information) and spec-
       ify a wildcard for all other destinations.

            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 the transport that matches
       the address domain class (see TRANSPORT FIELD discussion  above).   The
       following  sends  all mail for foo.org and its subdomains to host gate-

            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
       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 deliverable

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

       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.hierarchy 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  interpo-
       lated as $1, $2 and so on.

       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.

              The  address  that  is  looked  up  instead  of  the null sender

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

              List of transport lookup tables.

       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

       The Secure Mailer license must be distributed with this software.

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