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       canonical - Postfix canonical table format


       postmap /etc/postfix/canonical

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

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


       The  optional canonical(5) table specifies an address mapping 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

       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 regular-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

       By  default  the  canonical(5)  mapping  affects  both  message  header
       addresses (i.e. addresses that  appear  inside  messages)  and  message
       envelope  addresses  (for  example, the addresses that are used in SMTP
       protocol commands).  This  is  controlled  with  the  canonical_classes

       NOTE:  Postfix  versions  2.2  and  later  rewrite message headers from
       remote   SMTP   clients   only    if    the    client    matches    the
       local_header_rewrite_clients       parameter,       or      if      the
       remote_header_rewrite_domain configuration parameter specifies  a  non-
       empty   value.   To  get  the  behavior  before  Postfix  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

       The canonical(5) mapping is not  to  be  confused  with  virtual  alias
       support  or  with local aliasing. To change the destination but not the
       headers, use the virtual(5) or aliases(5) map instead.


       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  a  mail  address,  replace  it  by  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.


       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@domain address
              Replace user@domain  by  address.  This  form  has  the  highest

              This  is  useful  to  clean up addresses produced by legacy mail
              systems.  It can also  be  used  to  produce  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

       @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.


       The lookup result is subject to address rewriting:

       ·      When  the  result  has the form @otherdomain, the result becomes
              the same user in otherdomain.

       ·      When "append_at_myorigin=yes", append "@$myorigin" to  addresses
              without "@domain".

       ·      When "append_dot_mydomain=yes", append ".$mydomain" to addresses
              without ".domain".


       When a mail address localpart contains the optional recipient 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 propagated to the result of table


       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 table, 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.


       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 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.


       The table format does not understand quoting conventions.


       The  following  parameters  are especially relevant.  The text
       below provides only a  parameter  summary.  See  postconf(5)  for  more
       details including examples.

              What addresses are subject to canonical address mapping.

              List of canonical mapping tables.

              Address  mapping  lookup table for envelope and header recipient

              Address mapping lookup table  for  envelope  and  header  sender

              A  list  of  address  rewriting  or  forwarding  mechanisms 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:

              The network interface addresses that this system  receives  mail
              on.   You  need  to  stop  and start Postfix when this parameter

              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.

              Other  interfaces that this machine receives mail on by way of a
              proxy agent or network address translator.

              List of address classes subject to masquerading: zero or more of
              envelope_sender,        envelope_recipient,       header_sender,

              List of domains that hide their subdomain structure.

              List of user names that are not subject to address masquerading.

              List of domains that this mail system considers local.

              The domain that is appended to locally-posted mail.

              Give special treatment to owner-xxx and xxx-request addresses.

              Don’t  rewrite  message  headers from remote clients at all when
              this parameter is empty; otherwise, rewrite message headers  and
              append the specified domain name to incomplete addresses.


       cleanup(8), canonicalize and enqueue mail
       postmap(1), Postfix lookup table manager
       postconf(5), configuration parameters
       virtual(5), virtual aliasing


       Use  "postconf readme_directory" or "postconf html_directory" to locate
       this information.
       DATABASE_README, Postfix lookup table overview
       ADDRESS_REWRITING_README, address rewriting guide


       The Secure Mailer license must be distributed with this software.


       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA