Postfix canonical configuration example for CentOS Linux 8

Get the default configuration file canonical for Postfix, optimized for CentOS Linux 8. 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/canonical.

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

    # CANONICAL(5)                                                      CANONICAL(5)
# 
# NAME
#        canonical - Postfix canonical table format
# 
# SYNOPSIS
#        postmap /etc/postfix/canonical
# 
#        postmap -q "string" /etc/postfix/canonical
# 
#        postmap -q - /etc/postfix/canonical <inputfile
# 
# DESCRIPTION
#        The  optional canonical(5) table specifies an address map-
#        ping for local and non-local  addresses.  The  mapping  is
#        used  by the cleanup(8) daemon, before mail is stored into
#        the queue.  The address mapping is recursive.
# 
#        Normally, the canonical(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/canonical"  to  rebuild  an  indexed
#        file after changing the corresponding text file.
# 
#        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 regu-
#        lar-expression map where patterns  are  given  as  regular
#        expressions,  or  lookups  can  be  directed  to TCP-based
#        server. In those cases, the lookups are done in a slightly
#        different way as described below under "REGULAR EXPRESSION
#        TABLES" or "TCP-BASED TABLES".
# 
#        By default the canonical(5) mapping affects  both  message
#        header  addresses  (i.e. addresses that appear inside mes-
#        sages) and message envelope addresses  (for  example,  the
#        addresses  that  are used in SMTP protocol commands). This
#        is controlled with the canonical_classes parameter.
# 
#        NOTE: Postfix versions 2.2 and later rewrite message head-
#        ers  from  remote  SMTP clients only if the client matches
#        the  local_header_rewrite_clients  parameter,  or  if  the
#        remote_header_rewrite_domain configuration parameter spec-
#        ifies a non-empty value. To get the behavior before  Post-
#        fix    2.2,    specify   "local_header_rewrite_clients   =
#        static:all".
# 
#        Typically, one would use the canonical(5) table to replace
#        login   names   by  Firstname.Lastname,  or  to  clean  up
#        addresses produced by legacy mail systems.
# 
#        The canonical(5) mapping is not to be confused  with  vir-
#        tual  alias  support or with local aliasing. To change the
#        destination but not the headers,  use  the  virtual(5)  or
#        aliases(5) map instead.
# 
# 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 address
#               When  pattern matches a mail address, replace it by
#               the corresponding address.
# 
#        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.
# 
# TABLE SEARCH ORDER
#        With lookups from indexed files such as DB or DBM, or from
#        networked   tables   such   as  NIS,  LDAP  or  SQL,  each
#        user@domain query produces a sequence of query patterns as
#        described below.
# 
#        Each  query pattern is sent to each specified lookup table
#        before trying the next query pattern,  until  a  match  is
#        found.
# 
#        user@domain address
#               Replace  user@domain  by address. This form has the
#               highest precedence.
# 
#               This is useful to clean up  addresses  produced  by
#               legacy  mail  systems.  It can also be used to pro-
#               duce Firstname.Lastname style  addresses,  but  see
#               below for a simpler solution.
# 
#        user address
#               Replace  user@site by address when site is equal to
#               $myorigin, when site is listed  in  $mydestination,
#               or   when  it  is  listed  in  $inet_interfaces  or
#               $proxy_interfaces.
# 
#               This form is useful for replacing  login  names  by
#               Firstname.Lastname.
# 
#        @domain address
#               Replace other addresses in domain by address.  This
#               form has the lowest precedence.
# 
#               Note: @domain is a wild-card.  When  this  form  is
#               applied  to  recipient  addresses, the Postfix SMTP
#               server accepts mail for any  recipient  in  domain,
#               regardless  of whether that recipient exists.  This
#               may  turn  your  mail  system  into  a  backscatter
#               source: Postfix first accepts mail for non-existent
#               recipients and then tries to return  that  mail  as
#               "undeliverable" to the often forged sender address.
# 
# RESULT ADDRESS REWRITING
#        The lookup result is subject to address rewriting:
# 
#        o      When the result  has  the  form  @otherdomain,  the
#               result becomes the same user in otherdomain.
# 
#        o      When  "append_at_myorigin=yes", append "@$myorigin"
#               to addresses without "@domain".
# 
#        o      When "append_dot_mydomain=yes", append ".$mydomain"
#               to addresses without ".domain".
# 
# ADDRESS EXTENSION
#        When a mail address localpart contains the optional recip-
#        ient delimiter (e.g., user+foo@domain), the  lookup  order
#        becomes: user+foo@domain, user@domain, user+foo, user, and
#        @domain.
# 
#        The  propagate_unmatched_extensions   parameter   controls
#        whether  an  unmatched  address extension (+foo) is propa-
#        gated to the result of table lookup.
# 
# 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, user@domain mail
#        addresses  are  not  broken up into their user and @domain
#        constituent parts, nor is user+foo broken up into user and
#        foo.
# 
#        Patterns  are applied in the order as specified in the ta-
#        ble, 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.
# 
# 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 address once.  Thus,
#        user@domain mail addresses are not broken  up  into  their
#        user and @domain constituent parts, nor is user+foo broken
#        up into user and foo.
# 
#        Results are the same as with indexed file lookups.
# 
# BUGS
#        The table format does not understand quoting  conventions.
# 
# 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.
# 
#        canonical_classes
#               What  addresses  are  subject  to canonical address
#               mapping.
# 
#        canonical_maps
#               List of canonical mapping tables.
# 
#        recipient_canonical_maps
#               Address  mapping  lookup  table  for  envelope  and
#               header recipient addresses.
# 
#        sender_canonical_maps
#               Address  mapping  lookup  table  for  envelope  and
#               header sender addresses.
# 
#        propagate_unmatched_extensions
#               A list of address rewriting  or  forwarding  mecha-
#               nisms  that propagate an address extension from the
#               original address to the result.   Specify  zero  or
#               more   of   canonical,   virtual,  alias,  forward,
#               include, or generic.
# 
#        Other parameters of interest:
# 
#        inet_interfaces
#               The network interface addresses  that  this  system
#               receives mail on.  You need to stop and start Post-
#               fix when this parameter changes.
# 
#        local_header_rewrite_clients
#               Rewrite message header addresses in mail from these
#               clients  and  update  incomplete addresses with the
#               domain name in $myorigin or $mydomain; either don't
#               rewrite  message headers from other clients at all,
#               or rewrite message headers  and  update  incomplete
#               addresses   with   the   domain  specified  in  the
#               remote_header_rewrite_domain parameter.
# 
#        proxy_interfaces
#               Other interfaces that this machine receives mail on
#               by way of a proxy agent or network address transla-
#               tor.
# 
#        masquerade_classes
#               List of address classes  subject  to  masquerading:
#               zero  or  more of envelope_sender, envelope_recipi-
#               ent, header_sender, header_recipient.
# 
#        masquerade_domains
#               List of domains that hide  their  subdomain  struc-
#               ture.
# 
#        masquerade_exceptions
#               List  of user names that are not subject to address
#               masquerading.
# 
#        mydestination
#               List of domains that  this  mail  system  considers
#               local.
# 
#        myorigin
#               The domain that is appended to locally-posted mail.
# 
#        owner_request_special
#               Give special treatment to owner-xxx and xxx-request
#               addresses.
# 
#        remote_header_rewrite_domain
#               Don't  rewrite  message headers from remote clients
#               at all when this parameter is empty; otherwise, re-
#               write  message  headers  and  append  the specified
#               domain name to incomplete addresses.
# 
# SEE ALSO
#        cleanup(8), canonicalize and enqueue mail
#        postmap(1), Postfix lookup table manager
#        postconf(5), configuration parameters
#        virtual(5), virtual aliasing
# 
# README FILES
#        Use "postconf readme_directory" or  "postconf  html_direc-
#        tory" to locate this information.
#        DATABASE_README, Postfix lookup table overview
#        ADDRESS_REWRITING_README, address rewriting guide
# 
# 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
# 
#        Wietse Venema
#        Google, Inc.
#        111 8th Avenue
#        New York, NY 10011, USA
# 
#                                                                   CANONICAL(5)

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