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
              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. In that case, the lookups are done  in  a  slightly
       different  way as described in section "REGULAR EXPRESSION
       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.   The  trans-
       port  field  specifies  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
       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  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 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 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 foo:
       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
       something that runs at most  one  delivery  process  at  a
       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 and its subdomains to host
       In the above example, the  []  are  used  to  suppress  MX
       lookups.   The  result  would  likely  point to your local
       In the case of delivery via SMTP, one  may  specify  host-
       name:service instead of just a host:
       This  directs  mail  for to host 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:
        error:mail for * is not  deliv-
       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 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
       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.
       The  following parameters are especially relevant
       to this topic. See the Postfix  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 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.
       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
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA