# CANONICAL(5)                  File Formats Manual                 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 in‐
#        dexed files.
# 
#        Alternatively, the table can be provided as a  regular-ex‐
#        pression  map  where patterns are given as regular expres‐
#        sions, or lookups can be directed to a  TCP-based  server.
#        In those cases, the lookups are done in a slightly differ‐
#        ent  way  as described below under "REGULAR EXPRESSION TA‐
#        BLES" 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 re‐
#        mote_header_rewrite_domain configuration parameter  speci‐
#        fies 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 ad‐
#        dresses 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@do‐
#        main query produces a sequence of query  patterns  as  de‐
#        scribed 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
#               $proxy_interfaces.
# 
#               This form is useful for replacing  login  names  by
#               Firstname.Lastname.
# 
#        @domain address
#               Replace other addresses in domain by address.  This
#               form has the lowest precedence.
# 
#               Note: @domain is a wild-card. When this form is ap‐
#               plied  to  recipient  addresses,  the  Postfix SMTP
#               server accepts mail for any  recipient  in  domain,
#               regardless  of whether that recipient exists.  This
#               may  turn  your  mail  system  into  a  backscatter
#               source: Postfix first accepts mail for non-existent
#               recipients  and  then  tries to return that mail as
#               "undeliverable" to the often forged sender address.
# 
#               To avoid backscatter with mail for a wild-card  do‐
#               main,  replace  the wild-card mapping with explicit
#               1:1 mappings, or add a  reject_unverified_recipient
#               restriction for that domain:
# 
#                   smtpd_recipient_restrictions =
#                       ...
#                       reject_unauth_destination
#                       check_recipient_access
#                           inline:{example.com=reject_unverified_recipient}
#                   unverified_recipient_reject_code = 550
# 
#               In  the above example, Postfix may contact a remote
#               server if the recipient is rewritten  to  a  remote
#               address.
# 
# RESULT ADDRESS REWRITING
#        The lookup result is subject to address rewriting:
# 
#        •      When  the result has the form @otherdomain, the re‐
#               sult becomes the same user in otherdomain.
# 
#        •      When "append_at_myorigin=yes", append  "@$myorigin"
#               to addresses without "@domain".
# 
#        •      When "append_dot_mydomain=yes", append ".$mydomain"
#               to addresses without ".domain".
# 
# 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  ad‐
#               dress 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  local  network  interface  addresses that this
#               mail system receives mail on.
# 
#        local_header_rewrite_clients (permit_inet_interfaces)
#               Rewrite or add message headers in mail  from  these
#               clients, updating incomplete addresses with the do‐
#               main  name  in  $myorigin  or $mydomain, and adding
#               missing headers.
# 
#        proxy_interfaces (empty)
#               The remote network interface  addresses  that  this
#               mail  system  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  addresses
#               match $masquerade_domains.
# 
#        mydestination ($myhostname, localhost.$mydomain, local‐
#        host)
#               The list of domains that are delivered via the $lo‐
#               cal_transport mail delivery transport.
# 
#        myorigin ($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)
#               Rewrite  or add message headers in mail from remote
#               clients if the remote_header_rewrite_domain parame‐
#               ter value is  non-empty,  updating  incomplete  ad‐
#               dresses  with  the  domain  specified  in  the  re‐
#               mote_header_rewrite_domain  parameter,  and  adding
#               missing headers.
# 
# 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)
