Provided by: postfix_2.9.1-4_amd64 bug

NAME

       transport - Postfix transport table format

SYNOPSIS

       postmap /etc/postfix/transport

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

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

DESCRIPTION

       The  optional  transport(5)  table  specifies  a  mapping  from email addresses to message
       delivery transports and next-hop destinations.  Message delivery transports such as  local
       or  smtp  are defined in the master.cf file, and next-hop destinations are typically hosts
       or domain names. The table is searched by the trivial-rewrite(8) daemon.

       This mapping overrides the default transport:nexthop selection that is built into Postfix:

       local_transport (default: local:$myhostname)
              This is the default for final delivery to domains listed  with  mydestination,  and
              for  [ipaddress] destinations that match $inet_interfaces or $proxy_interfaces. The
              default nexthop destination is the MTA hostname.

       virtual_transport (default: virtual:)
              This   is   the   default   for   final   delivery   to   domains    listed    with
              virtual_mailbox_domains. The default nexthop destination is the recipient domain.

       relay_transport (default: relay:)
              This  is  the  default for remote delivery to domains listed with relay_domains. In
              order  of  decreasing  precedence,  the   nexthop   destination   is   taken   from
              relay_transport,  sender_dependent_relayhost_maps, relayhost, or from the recipient
              domain.

       default_transport (default: smtp:)
              This is the default for  remote  delivery  to  other  destinations.   In  order  of
              decreasing     precedence,     the    nexthop    destination    is    taken    from
              sender_dependent_default_transport_maps,                         default_transport,
              sender_dependent_relayhost_maps, relayhost, or from the recipient domain.

       Normally,  the  transport(5) 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" to
       rebuild an indexed file after changing the corresponding 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, or lookups can be directed to  TCP-based  server.  In  those
       case,  the  lookups are done in a slightly different way as described below under "REGULAR
       EXPRESSION TABLES" or "TCP-BASED TABLES".

CASE FOLDING

       The search string is folded to lowercase before database lookup. As of  Postfix  2.3,  the
       search string is not case folded with database types such as regexp: or pcre: whose lookup
       fields can match both upper and lower case.

TABLE FORMAT

       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 and specifies how or where to deliver mail.
       This is described in section "RESULT FORMAT".

TABLE SEARCH ORDER

       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
              Deliver mail for user+extension@domain through transport to nexthop.

       user@domain transport:nexthop
              Deliver mail for user@domain through transport to nexthop.

       domain transport:nexthop
              Deliver mail for domain through transport to nexthop.

       .domain transport:nexthop
              Deliver mail for any subdomain of domain 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 subdomains.

       * transport:nexthop
              The special pattern * represents any address (i.e. it functions  as  the  wild-card
              pattern, and is unique to Postfix transport tables).

       Note  1:  the  null recipient address is looked up as $empty_address_recipient@$myhostname
       (default: mailer-daemon@hostname).

       Note 2: user@domain or user+extension@domain lookup is available in Postfix 2.0 and later.

RESULT FORMAT

       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 master.cf 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 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.

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  transport  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 example.com and its subdomains via the uucp transport to the
       UUCP host named example:

            example.com      uucp:example
            .example.com     uucp:example

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

            example.com      slow:

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

            example.com      :[gateway.example.com]
            .example.com     :[gateway.example.com]

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

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

            example.com      smtp:bar.example:2025

       This directs mail for user@example.com  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:

            .example.com     error:mail for *.example.com is not deliverable

       This causes all mail for user@anything.example.com 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  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 string.

       The  trivial-rewrite(8)  server  disallows  regular  expression substitution of $1 etc. in
       regular expression lookup tables, because that could open a security hole (Postfix version
       2.3 and later).

TCP-BASED TABLES

       This  section  describes  how the table lookups change when lookups are directed to a TCP-
       based  server.  For  a  description  of  the  TCP  client/server  lookup   protocol,   see
       tcp_table(5).  This feature is not available up to and including Postfix version 2.4.

       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 user@domain.

       Results are the same as with indexed file lookups.

CONFIGURATION PARAMETERS

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

       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 patterns to match sub.domain.tld (as
              opposed to requiring .domain.tld patterns).

       transport_maps
              List of transport lookup tables.

SEE ALSO

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

README FILES

       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       ADDRESS_REWRITING_README, address rewriting guide
       DATABASE_README, Postfix lookup table overview
       FILTER_README, external content filter

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)