TRANSPORT(5)                                                      TRANSPORT(5)

       transport - Postfix transport table format

       postmap /etc/postfix/transport

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

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

       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 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] des-
              tinations    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_depen-
              dent_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 expres-
       sions,  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".

       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.

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

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

       domain transport:nexthop
              Deliver  mail  for domain through transport to nex-

       .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  par-
              ent_domain_matches_subdomains   configuration  set-
              ting.  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-dae-

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

       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 deliverable

       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  ta-
       ble,  until  a  pattern  is  found that matches the search

       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).

       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_ta-
       ble(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

       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
       master(5), file format
       postconf(5), configuration parameters
       postmap(1), Postfix lookup table manager

       ADDRESS_REWRITING_README, address rewriting guide
       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