Provided by: postfix_2.5.1-2ubuntu1_i386 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  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.

       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).

       Note  3:  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)