TRANSPORT(5)                                         TRANSPORT(5)

       transport - format of Postfix transport table

       postmap /etc/postfix/transport

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

       postmap -q - /etc/postfix/transport <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)

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

              A  list of domains that is by default delivered via
              $local_transport. This also includes  domains  that
              match $inet_interfaces or $proxy_interfaces.

              A  list of domains that is by default delivered via

              A list of domains that is by default delivered  via

       any other destination
              Mail for any other destination is by default deliv-
              ered via $default_transport.

       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 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".

       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 logi-
              cal line.

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

       The result is of the form transport:nexthop and  specifies
       how or where to deliver mail. This is described in section

       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

       .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 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-dae-

       The  lookup  result is of the form transport:nexthop.  The
       transport field specifies a mail delivery  transport  such
       as  smtp  or  local. The nexthop field specifies where and
       how to deliver mail.

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

       The interpretation  of  the  nexthop  field  is  transport
       dependent.  In  the  case  of SMTP, specify a service on a
       non-default port as host:service,  and  disable  MX  (mail
       exchanger)  DNS lookups with [host] or [host]:port. 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  informa-
       tion  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  trans-
       port  or  the  nexthop information) and specify a wildcard
       for all other destinations.

            my.domain    :
            .my.domain   :

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


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


       When no transport is specified, Postfix uses the transport
       that  matches  the  address  domain class (see DESCRIPTION
       above).  The following sends all mail for  and
       its subdomains to host


       In  the  above  example, the [] suppress MX lookups.  This
       prevents mail routing loops when your machine  is  primary
       MX host for

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


       This directs mail for to host bar.example
       port 2025. Instead of a numerical port a symbolic name may
       be used. Specify [] around the hostname if MX lookups must
       be disabled.

       The error mailer can be used to bounce mail:

        error:mail for * is not

       This causes all mail for  to  be

       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    address    being    looked    up.   Thus,
       some.domain.hierarchy is not  looked  up  via  its  parent
       domains,  nor is user+foo@domain looked up as user@domain.

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

       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.

       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  recipient  address
       once.   Thus,  some.domain.hierarchy  is not looked up via
       its parent domains, nor is user+foo@domain  looked  up  as

       Results are the same as with indexed file lookups.

       The  following parameters are especially relevant.
       The text below provides  only  a  parameter  summary.  See
       postconf(5) for more details including examples.

              The  address  that is looked up instead of the null
              sender address.

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

              List of transport lookup tables.

       trivial-rewrite(8), rewrite and resolve addresses
       postconf(5), configuration parameters
       postmap(1), Postfix lookup table manager

       DATABASE_README, Postfix lookup table overview
       FILTER_README, external content filter

       The  Secure  Mailer  license must be distributed with this

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