Postfix transport configuration example for CentOS Linux 6

Get the default configuration file transport for Postfix, optimized for CentOS Linux 6. This example configuration ensures optimal compatibility and performance for Postfix, making it easy to set up and adjust to meet your needs.

Find and download the configuration file here: /etc/postfix/transport.

For more configurations and setup guides, visit our related files section to further customize your system.

    # TRANSPORT(5)                                                      TRANSPORT(5)
# 
# 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] 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
#               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".
# 
# 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 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 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  nex-
#               thop.
# 
#        .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-
#        mon@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  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 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 host-
#        name: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 ta-
#        ble, 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 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
#        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  pat-
#               terns   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_direc-
#        tory" 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)

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