# TRANSPORT(5)                                         TRANSPORT(5)
# 
# NAME
#        transport - format of Postfix transport table
# 
# SYNOPSIS
#        postmap /etc/postfix/transport
# 
#        postmap -q "string" /etc/postfix/transport
# 
#        postmap -q - /etc/postfix/transport <inputfile
# 
# DESCRIPTION
#        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.
# 
#        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
#        TABLES".
# 
# TABLE FORMAT
#        The format of the transport table 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
#        LOOKUP".
# 
#        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
#        FORMAT".
# 
# TABLE LOOKUP
#        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
#               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 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-
#        mon@hostname).
# 
# RESULT FORMAT
#        The  transport field specifies the name of a mail delivery
#        transport (the first name of a mail delivery service entry
#        in the Postfix master.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 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.
# 
# EXAMPLES
#        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   :
#             *            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 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.
# 
#        empty_address_recipient
#               The address that is looked up instead of  the  null
#               sender address.
# 
#        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.
# 
# 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)
