# 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 rewrites recipient
#        addresses for all local, all virtual, and all remote  mail
#        destinations.   This  is unlike the aliases(5) table which
#        is used only for local(8) delivery.  Virtual  aliasing  is
#        recursive,  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.   Use
#        canonical(5)   mapping  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" 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
#        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
#        those case, the lookups are done in a  slightly  different
#        way  as  described below under "REGULAR EXPRESSION TABLES"
#        or "TCP-BASED TABLES".
# 
# 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 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 $proxy_interfaces.
# 
#               This  functionality  overlaps with functionality of
#               the local aliases(5) database.  The  difference  is
#               that virtual(5) mapping can be applied to non-local
#               addresses.
# 
#        @domain address, address, ...
#               Redirect mail for other users in domain to address.
#               This form has the lowest precedence.
# 
#               Note:  @domain  is a wild-card. With this form, the
#               Postfix SMTP server accepts mail for any  recipient
#               in  domain,  regardless  of  whether that recipient
#               exists.  This may turn  your  mail  system  into  a
#               backscatter  source: Postfix first accepts mail for
#               non-existent recipients and then  tries  to  return
#               that  mail  as  "undeliverable" to the often forged
#               sender address.
# 
# RESULT ADDRESS REWRITING
#        The lookup result is subject to address rewriting:
# 
#        o      When the result  has  the  form  @otherdomain,  the
#               result  becomes the same user in otherdomain.  This
#               works only for the first address in a multi-address
#               lookup result.
# 
#        o      When  "append_at_myorigin=yes", append "@$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:
# 
#        /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 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
#        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.
#        ADDRESS_REWRITING_README, address rewriting guide
#        DATABASE_README, Postfix lookup table overview
#        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)
