CANONICAL(5)                                         CANONICAL(5)

NAME
       canonical - format of Postfix canonical table

SYNOPSIS
       postmap /etc/postfix/canonical

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

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

DESCRIPTION
       The  optional canonical table specifies an address mapping
       for local and non-local addresses. The mapping is used  by
       the  cleanup(8) daemon.  The address mapping is recursive.

       Normally, the canonical 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 in  order  to  rebuild  the
       indexed file after changing the 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 expres-
       sions.  In  that  case, the lookups are done in a slightly
       different way as described below.

       The  canonical  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). Think Sendmail
       rule set S3, if you like.

       Typically, one would use the canonical  table  to  replace
       login   names   by  Firstname.Lastname,  or  to  clean  up
       addresses produced by legacy mail systems.

       The canonical mapping is not to be confused  with  virtual
       domain support. Use the virtual(5) map for that purpose.

       The  canonical  mapping  is  not to be confused with local
       aliasing.  Use the aliases(5) map for that purpose.

TABLE FORMAT
       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 logi-
              cal 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
              user@domain is replaced 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
              user@site is replaced by address when site is equal
              to  $myorigin,  when  site is listed in $mydestina-
              tion, or when it is listed in $inet_interfaces.

              This form is useful for replacing  login  names  by
              Firstname.Lastname.

       @domain address
              Every  address  in  domain  is replaced by address.
              This form has the lowest precedence.

       In all the above forms, when address has the form  @other-
       domain, the result is the same user in otherdomain.

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.  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
       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.

BUGS
       The table format does not understand quoting  conventions.

CONFIGURATION PARAMETERS
       The  following  main.cf parameters are especially relevant
       to this topic. See the Postfix  main.cf  file  for  syntax
       details  and  for  default  values. Use the postfix reload
       command after a configuration change.

       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.

       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.

       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.

SEE ALSO
       cleanup(8) canonicalize and enqueue mail
       postmap(1) create mapping table
       virtual(5) virtual domain mapping
       pcre_table(5) format of PCRE tables
       regexp_table(5) format of POSIX regular expression tables

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

                                                     CANONICAL(5)