# VIRTUAL(5)                                                          VIRTUAL(5)
# 
# NAME
#        virtual - Postfix virtual alias table format
# 
# SYNOPSIS
#        postmap /usr/local/etc/postfix/virtual
# 
#        postmap -q "string" /usr/local/etc/postfix/virtual
# 
#        postmap -q - /usr/local/etc/postfix/virtual <inputfile
# 
# DESCRIPTION
#        The  optional  virtual(5)  alias  table rewrites recipient
#        addresses for all local, virtual and remote mail  destina-
#        tions.   This is unlike the aliases(5) table which is used
#        only for local(8) delivery.  Virtual  aliasing  is  recur-
#        sive,  and is implemented by the Postfix cleanup(8) daemon
#        before mail is queued.
# 
#        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  /usr/local/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 $proxy_interfaces.
# 
#               This  functionality  overlaps with functionality of
#               the local aliases(5) database.  The  difference  is
#               that virtual(5) mapping can be applied to non-local
#               addresses.
# 
#        @domain address, address, ...
#               Redirect mail for other users in domain to address.
#               This form has the lowest precedence.
# 
# RESULT ADDRESS REWRITING
#        The lookup result is subject to address rewriting:
# 
#        o      When  the  result  has  the  form @otherdomain, the
#               result becomes the same user in otherdomain.   This
#               works only for the first address in a multi-address
#               lookup result.
# 
#        o      When "append_at_myorigin=yes", append  "@$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 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:
# 
#        /usr/local/etc/postfix/main.cf:
#            virtual_alias_maps = hash:/usr/local/etc/postfix/virtual
# 
#            Note: some systems use dbm databases instead of  hash.
#            See  the output from "postconf -m" for available data-
#            base types.
# 
#        /usr/local/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  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 2.2.
# 
#        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 generic.
# 
#        Other parameters of interest:
# 
#        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)
