# 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 to
#        create an indexed file for fast lookup.
# 
#        Execute the command  "postmap  /etc/postfix/canonical"  to
#        rebuild  a  default-type  indexed  file after changing the
#        text file, or execute  "postmap  type:/etc/postfix/canoni‐
#        cal" to specify an explicit type.
# 
#        The  default  indexed file type is configured with the de‐
#        fault_database_type parameter. Depending on  the  platform
#        this  may  be  one of lmdb:, cdb:, hash:, or dbm: (without
#        the trailing ':').
# 
#        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.  Managing such databases is outside the scope
#        of Postfix.
# 
#        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)
