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 format of the canonical table 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)