# VIRTUAL(5)                                             VIRTUAL(5)
# 
# NAME
#        virtual - Postfix virtual alias table format
# 
# SYNOPSIS
#        postmap /etc/postfix/virtual
# 
#        postmap -q "string" /etc/postfix/virtual
# 
#        postmap -q - /etc/postfix/virtual <inputfile
# 
# DESCRIPTION
#        The  optional  virtual(5)  alias  table  specifies address
#        aliasing  for  arbitrary  local  or  non-local   recipient
#        addresses.  Virtual  aliasing is recursive, and is done by
#        the Postfix cleanup(8) daemon.
# 
#        The main applications of virtual aliasing are:
# 
#        o      To redirect mail for one address  to  one  or  more
#               addresses.
# 
#        o      To   implement  virtual  alias  domains  where  all
#               addresses  are  aliased  to  addresses   in   other
#               domains.
# 
#               Virtual  alias  domains are not to be confused with
#               the virtual mailbox domains  that  are  implemented
#               with  the  Postfix  virtual(8) mail delivery agent.
#               With  virtual  mailbox  domains,   each   recipient
#               address can have its own mailbox.
# 
#        Virtual  aliasing  is  applied  only to recipient envelope
#        addresses, and does not  affect  message  headers.   Think
#        Sendmail  rule  set S0, if you like. Use canonical(5) map-
#        ping to rewrite header and envelope addresses in  general.
# 
#        Normally,  the  virtual(5)  alias  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, or lookups can be directed to TCP-based server.  In
#        that  case,  the  lookups are done in a slightly different
#        way as described below under "REGULAR  EXPRESSION  TABLES"
#        and "TCP-BASED TABLES".
# 
# TABLE FORMAT
#        The input format for the postmap(1) command 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.
# 
# 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, address, ...
#               Redirect  mail  for  user@domain  to address.  This
#               form has the highest precedence.
# 
#        user address, address, ...
#               Redirect mail for user@site to address when site is
#               equal  to $myorigin, when site is listed in $mydes-
#               tination, or when it is listed in  $inet_interfaces
#               or $proxy_interfaces.
# 
#               This  functionality  overlaps with functionality of
#               the local aliases(5) database.  The  difference  is
#               that virtual(5) mapping can be applied to non-local
#               addresses.
# 
#        @domain address, address, ...
#               Redirect mail for other users in domain to address.
#               This form has the lowest precedence.
# 
# 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.   This
#               works only for the first address in a multi-address
#               lookup result.
# 
#        o      The  result  is   rewritten   as   specified   with
#               append_at_myorigin or with append_dot_mydomain.
# 
# 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.
# 
# VIRTUAL ALIAS DOMAINS
#        Besides virtual aliases, the virtual alias table can  also
#        be used to implement virtual alias domains. With a virtual
#        alias domain,  all  recipient  addresses  are  aliased  to
#        addresses in other domains.
# 
#        Virtual alias domains are not to be confused with the vir-
#        tual mailbox domains that are implemented with the Postfix
#        virtual(8)  mail  delivery  agent.  With  virtual  mailbox
#        domains, each recipient address can have its own  mailbox.
# 
#        With  a  virtual  alias domain, the virtual domain has its
#        own user name space. Local  (i.e.  non-virtual)  usernames
#        are  not visible in a virtual alias domain. In particular,
#        local aliases(5) and local mailing lists are  not  visible
#        as localname@virtual-alias.domain.
# 
#        Support for a virtual alias domain looks like:
# 
#        /etc/postfix/main.cf:
#            virtual_alias_maps = hash:/etc/postfix/virtual
# 
#            Note:  some systems use dbm databases instead of hash.
#            See  the  output  from  "postconf  -m"  for  available
#            database types.
# 
#        /etc/postfix/virtual:
#            virtual-alias.domain anything (right-hand content does not matter)
#            postmaster@virtual-alias.domain      postmaster
#            user1@virtual-alias.domain   address1
#            user2@virtual-alias.domain   address2, address3
# 
#        The  virtual-alias.domain anything entry is required for a
#        virtual alias domain. Without this entry, mail is rejected
#        with  "relay  access  denied", or bounces with "mail loops
#        back to myself".
# 
#        Do not specify virtual alias domain names in  the  main.cf
#        mydestination or relay_domains configuration parameters.
# 
#        With  a  virtual  alias  domain,  the  Postfix SMTP server
#        accepts  mail  for  known-user@virtual-alias.domain,   and
#        rejects   mail  for  unknown-user@virtual-alias.domain  as
#        undeliverable.
# 
#        Instead of specifying the virtual alias  domain  name  via
#        the  virtual_alias_maps table, you may also specify it via
#        the main.cf virtual_alias_domains configuration parameter.
#        This  latter parameter uses the same syntax as the main.cf
#        mydestination configuration parameter.
# 
# 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, $2 and so on.
# 
# TCP-BASED TABLES
#        This  section  describes how the table lookups change when
#        lookups are directed to a TCP-based server. For a descrip-
#        tion   of  the  TCP  client/server  lookup  protocol,  see
#        tcp_table(5).  This feature is not  available  up  to  and
#        including Postfix version 2.2.
# 
#        Each lookup operation uses the entire address once.  Thus,
#        user@domain mail addresses are not broken  up  into  their
#        user and @domain constituent parts, nor is user+foo broken
#        up into user and foo.
# 
#        Results are the same as with indexed file lookups.
# 
# BUGS
#        The table format does not understand quoting  conventions.
# 
# CONFIGURATION PARAMETERS
#        The  following  main.cf parameters are especially relevant
#        to this topic. See the Postfix  main.cf  file  for  syntax
#        details  and  for default values. Use the "postfix reload"
#        command after a configuration change.
# 
#        virtual_alias_maps
#               List of virtual aliasing tables.
# 
#        virtual_alias_domains
#               List of virtual alias domains. This uses  the  same
#               syntax as the mydestination parameter.
# 
#        propagate_unmatched_extensions
#               A  list  of  address rewriting or forwarding mecha-
#               nisms that propagate an address extension from  the
#               original  address  to  the result.  Specify zero or
#               more  of  canonical,   virtual,   alias,   forward,
#               include, or generics.
# 
#        Other parameters of interest:
# 
#        append_at_myorigin
#               Do  or don't append "@$myorigin" to addresses with-
#               out domain.  This must be turned on in Postfix.
# 
#        append_dot_mydomain
#               Do or don't append ".$mydomain" to addresses  with-
#               out "." on the right-hand side of the @.
# 
#        inet_interfaces
#               The  network  interface  addresses that this system
#               receives mail on.  You need to stop and start Post-
#               fix when this parameter changes.
# 
#        mydestination
#               List  of  domains  that  this mail system considers
#               local.
# 
#        myorigin
#               The domain that is appended  to  any  address  that
#               does not have a domain.
# 
#        owner_request_special
#               Give special treatment to owner-xxx and xxx-request
#               addresses.
# 
#        proxy_interfaces
#               Other interfaces that this machine receives mail on
#               by way of a proxy agent or network address transla-
#               tor.
# 
# SEE ALSO
#        cleanup(8), canonicalize and enqueue mail
#        postmap(1), Postfix lookup table manager
#        postconf(5), configuration parameters
#        canonical(5), canonical address mapping
# 
# 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
#        VIRTUAL_README, domain hosting 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
# 
#                                                        VIRTUAL(5)
