    VIRTUAL(5)                                             VIRTUAL(5)

    NAME
           virtual - format of Postfix virtual table

    SYNOPSIS
           postmap /etc/postfix/virtual

    DESCRIPTION
           The  optional virtual table specifies address redirections
           for local and non-local recipients or domains.  The  redi-
           rections  are  used by the cleanup(8) daemon. The redirec-
           tions are recursive.

           The virtual redirection is applied only to recipient enve-
           lope  addresses,  and  does  not  affect  message headers.
           Think Sendmail rule set S0, if you like. Use  canonical(5)
           mapping  to  rewrite header and envelope addresses in gen-
           eral.

           Normally, the virtual 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/virtual  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.

    POSTFIX-STYLE VIRTUAL DOMAINS
           With a Postfix-style virtual domain,  the  virtual  domain
           has  its  own  user  name  space. Local (i.e. non-virtual)
           usernames are  not  visible  in  a  Postfix-style  virtual
           domain.  In particular, local aliases(5) and mailing lists
           are not visible as localname@virtual.domain.

           Use a Sendmail-style virtual domain (see below)  if  local
           usernames,  aliases(5)  or mailing lists should be visible
           as localname@virtual.domain.

           Support for a Postfix-style virtual domain looks like:

           /etc/postfix/virtual:
               virtual.domain       anything (right-hand content does not matter)
               postmaster@virtual.domain    postmaster
               user1@virtual.domain address1
               user2@virtual.domain address2, address3

           The virtual.domain anything entry is required for a  Post-
           fix-style virtual domain.

           Do  not list a Postfix-style virtual domain in the main.cf
           mydestination configuration parameter.  Such an  entry  is
           required only for a Sendmail-style virtual domain.

           With  a  Postfix-style  virtual  domain,  the Postfix SMTP
           server  accepts  mail  for  known-user@virtual.domain  and
           rejects mail for unknown-user@virtual.domain as undeliver-
           able.

    SENDMAIL-STYLE VIRTUAL DOMAINS
           With a Sendmail-style virtual domain,  every  local  (i.e.
           non-virtual) username is visible in the virtual domain. In
           particular, every local alias and mailing list is  visible
           as localname@virtual.domain.

           Use  a  Postfix-style  virtual domain (see above) if local
           usernames, aliases(5) or mailing lists should not be visi-
           ble as localname@virtual.domain.

           Support for a Sendmail-style virtual domain looks like:

           /etc/postfix/main.cf:
               mydestination = $myhostname localhost.$mydomain $mydomain
                   virtual.domain

           /etc/postfix/virtual:
               user1@virtual.domain address1
               user2@virtual.domain address2, address3

           The  main.cf  mydestination  entry is required for a Send-
           mail-style virtual domain.

           Do not specify a virtual.domain anything virtual map entry
           for  a  Sendmail-style  virtual  domain.  Such an entry is
           required only with a Postfix-style virtual domain.

           With a Sendmail-style virtual domain,  the  Postfix  local
           delivery  agent  delivers  mail  for  an unknown user@vir-
           tual.domain to a local (i.e.  non-virtual) user  that  has
           the  same  name;  if no such recipient exists, the Postfix
           local delivery agent bounces the mail to the sender.

    TABLE FORMAT
           The format of the virtual table is  as  follows,  mappings
           being tried in the order as listed in this manual page:

           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, address, ...
                  Mail for  user@domain  is  redirected  to  address.
                  This form has the highest precedence.

           user address, address, ...
                  Mail  for  user@site  is redirected to address when
                  site is equal to $myorigin, when site is listed  in
                  $mydestination,   or   when   it   is   listed   in
                  $inet_interfaces.

                  This functionality overlaps with  functionality  of
                  the local alias(5) database. The difference is that
                  virtual  mapping  can  be  applied   to   non-local
                  addresses.

           @domain address, address, ...
                  Mail  for  any  user  in  domain  is  redirected to
                  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.  This
           works for the first address in the expansion only.

    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.

           virtual_maps
                  List of virtual mapping tables.

           Other parameters of interest:

           inet_interfaces
                  The  network  interface  addresses that this system
                  receives mail on.

           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
           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

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