Postfix canonical configuration example for Alpine Linux v3

Get the default configuration file canonical for Postfix, optimized for Alpine Linux v3. 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
#               $proxy_interfaces.
# 
#               This form is useful for replacing  login  names  by
#               Firstname.Lastname.
# 
#        @domain address
#               Replace other addresses in domain by address.  This
#               form has the lowest precedence.
# 
#               Note: @domain is a wild-card.  When  this  form  is
#               applied  to  recipient  addresses, the Postfix SMTP
#               server accepts mail for any  recipient  in  domain,
#               regardless  of whether that recipient exists.  This
#               may  turn  your  mail  system  into  a  backscatter
#               source: Postfix first accepts mail for non-existent
#               recipients and then tries to return  that  mail  as
#               "undeliverable" to the often forged sender address.
# 
#               To avoid backscatter  with  mail  for  a  wild-card
#               domain, replace the wild-card mapping with explicit
#               1:1 mappings, or add a  reject_unverified_recipient
#               restriction for that domain:
# 
#                   smtpd_recipient_restrictions =
#                       ...
#                       reject_unauth_destination
#                       check_recipient_access
#                           inline:{example.com=reject_unverified_recipient}
#                   unverified_recipient_reject_code = 550
# 
#               In  the above example, Postfix may contact a remote
#               server if the recipient is rewritten  to  a  remote
#               address.
# 
# RESULT ADDRESS REWRITING
#        The lookup result is subject to address rewriting:
# 
#        o      When  the  result  has  the  form @otherdomain, the
#               result becomes the same user in otherdomain.
# 
#        o      When "append_at_myorigin=yes", append  "@$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  (envelope_sender,   envelope_recipient,
#        header_sender, header_recipient)
#               What  addresses  are  subject   to   canonical_maps
#               address mapping.
# 
#        canonical_maps (empty)
#               Optional  address mapping lookup tables for message
#               headers and envelopes.
# 
#        recipient_canonical_maps (empty)
#               Optional address mapping lookup tables for envelope
#               and header recipient addresses.
# 
#        sender_canonical_maps (empty)
#               Optional address mapping lookup tables for envelope
#               and header sender addresses.
# 
#        propagate_unmatched_extensions (canonical, virtual)
#               What address lookup tables copy an  address  exten-
#               sion from the lookup key to the lookup result.
# 
#        Other parameters of interest:
# 
#        inet_interfaces (all)
#               The network interface addresses that this mail sys-
#               tem receives mail on.
# 
#        local_header_rewrite_clients (permit_inet_interfaces)
#               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 (empty)
#               The network interface addresses that this mail sys-
#               tem  receives  mail on by way of a proxy or network
#               address translation unit.
# 
#        masquerade_classes    (envelope_sender,     header_sender,
#        header_recipient)
#               What addresses are subject to address masquerading.
# 
#        masquerade_domains (empty)
#               Optional  list of domains whose subdomain structure
#               will be stripped off in email addresses.
# 
#        masquerade_exceptions (empty)
#               Optional list of user names that are not  subjected
#               to  address  masquerading,  even when their address
#               matches $masquerade_domains.
# 
#        mydestination  ($myhostname,  localhost.$mydomain,  local-
#        host)
#               The list of domains  that  are  delivered  via  the
#               $local_transport mail delivery transport.
# 
#        myorigin ($myhostname)
#               The domain name that locally-posted mail appears to
#               come from, and that locally posted mail  is  deliv-
#               ered to.
# 
#        owner_request_special (yes)
#               Enable special treatment for owner-listname entries
#               in the aliases(5) file, and don't split owner-list-
#               name  and  listname-request address localparts when
#               the recipient_delimiter is set to "-".
# 
#        remote_header_rewrite_domain (empty)
#               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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