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CANONICAL(5)		      File Formats Manual		  CANONICAL(5)

NAME
       canonical - Postfix canonical table format

SYNOPSIS
       postmap /usr/local/etc/postfix/canonical

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

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

DESCRIPTION
       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	recur-
       sive.

       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. Ex-
       ecute the command "postmap /usr/local/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  di-
       rected  to  TCP-based server. In	those cases, the lookups are done in a
       slightly	different way as described below under "REGULAR	EXPRESSION TA-
       BLES" or	"TCP-BASED TABLES".

       By  default  the	 canonical(5)  mapping affects both message header ad-
       dresses (i.e. addresses that appear inside messages) and	message	 enve-
       lope addresses (for example, the	addresses that are used	in SMTP	proto-
       col commands). This is controlled with the canonical_classes parameter.

       NOTE: Postfix versions 2.2 and later rewrite message headers  from  re-
       mote  SMTP  clients  only  if  the  client matches the local_header_re-
       write_clients parameter,	or if the remote_header_rewrite_domain config-
       uration	parameter specifies a non-empty	value. To get the behavior be-
       fore 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
       systems.

       The canonical(5)	mapping	is not to be confused with virtual alias  sup-
       port  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	corre-
	      sponding 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 logical line.

TABLE SEARCH ORDER
       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	prece-
	      dence.

	      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 Firstname.Last-
	      name.

       @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 re-
	      cipient addresses, the Postfix SMTP server accepts mail for  any
	      recipient	 in  domain,  regardless of whether that recipient ex-
	      ists.  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 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  un-
       matched	address	 extension (+foo) is propagated	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  ad-
       dress  being looked up. Thus, user@domain mail addresses	are not	broken
       up into their user and @domain constituent parts, nor is	user+foo  bro-
       ken 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 interpo-
       lated 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  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  con-
       stituent	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 be-
       low 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  ad-
	      dresses.

       propagate_unmatched_extensions
	      A	list of	address	rewriting or forwarding	mechanisms that	propa-
	      gate an address extension	from the original address to  the  re-
	      sult.   Specify  zero or more of canonical, virtual, alias, for-
	      ward, 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 Postfix 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_re-
	      write_domain parameter.

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

       masquerade_classes
	      List of address classes subject to masquerading: zero or more of
	      envelope_sender,	envelope_recipient,  header_sender, header_re-
	      cipient.

       masquerade_domains
	      List of domains that hide	their subdomain	structure.

       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, rewrite 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_directory" 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

								  CANONICAL(5)

NAME | SYNOPSIS | DESCRIPTION | CASE FOLDING | TABLE FORMAT | TABLE SEARCH ORDER | RESULT ADDRESS REWRITING | ADDRESS EXTENSION | REGULAR EXPRESSION TABLES | TCP-BASED TABLES | BUGS | CONFIGURATION PARAMETERS | SEE ALSO | README FILES | LICENSE | AUTHOR(S)

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