virtual.5.html   [plain text]

<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
<html> <head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<title> Postfix manual - virtual(5) </title>
</head> <body> <pre>
VIRTUAL(5)                                                          VIRTUAL(5)

       virtual - Postfix virtual alias table format

       <b>postmap /etc/postfix/virtual</b>

       <b>postmap -q "</b><i>string</i><b>" /etc/postfix/virtual</b>

       <b>postmap -q - /etc/postfix/virtual</b> &lt;<i>inputfile</i>

       The  optional  <a href="virtual.5.html"><b>virtual</b>(5)</a>  alias  table rewrites recipient
       addresses for all local, all virtual, and all remote  mail
       destinations.   This  is unlike the <a href="aliases.5.html"><b>aliases</b>(5)</a> table which
       is used only for <a href="local.8.html"><b>local</b>(8)</a> delivery.  Virtual  aliasing  is
       recursive,  and  is  implemented by the Postfix <a href="cleanup.8.html"><b>cleanup</b>(8)</a>
       daemon before mail is queued.

       The main applications of virtual aliasing are:

       <b>o</b>      To redirect mail for one address  to  one  or  more

       <b>o</b>      To   implement  virtual  alias  domains  where  all
              addresses  are  aliased  to  addresses   in   other

              Virtual  alias  domains are not to be confused with
              the <a href="ADDRESS_CLASS_README.html#virtual_mailbox_class">virtual mailbox domains</a>  that  are  implemented
              with  the  Postfix  <a href="virtual.8.html"><b>virtual</b>(8)</a> 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
       <a href="canonical.5.html"><b>canonical</b>(5)</a>   mapping  to  rewrite  header  and  envelope
       addresses in general.

       Normally, the <a href="virtual.5.html"><b>virtual</b>(5)</a> alias table  is  specified  as  a
       text  file that serves as input to the <a href="postmap.1.html"><b>postmap</b>(1)</a> command.
       The result, an indexed file in <b>dbm</b> or <b>db</b> format,  is  used
       for fast searching by the mail system. Execute the command
       "<b>postmap /etc/postfix/virtual</b>" 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".

       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 <a href="regexp_table.5.html">regexp</a>: or <a href="pcre_table.5.html">pcre</a>:  whose
       lookup fields can match both upper and lower case.

       The input format for the <a href="postmap.1.html"><b>postmap</b>(1)</a> command is as follows:

       <i>pattern result</i>
              When <i>pattern</i> matches a mail address, replace it  by
              the corresponding <i>result</i>.

       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:

       <i>user</i>@<i>domain address, address, ...</i>
              Redirect  mail  for  <i>user</i>@<i>domain</i>  to <i>address</i>.  This
              form has the highest precedence.

       <i>user address, address, ...</i>
              Redirect mail for <i>user</i>@<i>site</i> to <i>address</i> when <i>site</i> is
              equal  to $<b><a href="postconf.5.html#myorigin">myorigin</a></b>, when <i>site</i> is listed in $<b><a href="postconf.5.html#mydestination">mydes</a>-</b>
              <b><a href="postconf.5.html#mydestination">tination</a></b>, or when it is listed in  $<b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b>
              or $<b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a></b>.

              This  functionality  overlaps with functionality of
              the local <i>aliases</i>(5) database.  The  difference  is
              that <a href="virtual.5.html"><b>virtual</b>(5)</a> mapping can be applied to non-local

       @<i>domain address, address, ...</i>
              Redirect mail for other users in <i>domain</i> to <i>address</i>.
              This form has the lowest precedence.

              Note:  @<i>domain</i>  is a wild-card. With this form, the
              Postfix SMTP server accepts mail for any  recipient
              in  <i>domain</i>,  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.

       The lookup result is subject to address rewriting:

       <b>o</b>      When the result  has  the  form  @<i>otherdomain</i>,  the
              result  becomes the same <i>user</i> in <i>otherdomain</i>.  This
              works only for the first address in a multi-address
              lookup result.

       <b>o</b>      When  "<b><a href="postconf.5.html#append_at_myorigin">append_at_myorigin</a>=yes</b>", append "<b>@$<a href="postconf.5.html#myorigin">myorigin</a></b>"
              to addresses without "@domain".

       <b>o</b>      When "<b><a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a>=yes</b>", append "<b>.$<a href="postconf.5.html#mydomain">mydomain</a></b>"
              to addresses without ".domain".

       When a mail address localpart contains the optional recip-
       ient delimiter (e.g., <i>user+foo</i>@<i>domain</i>), the  lookup  order
       becomes: <i>user+foo</i>@<i>domain</i>, <i>user</i>@<i>domain</i>, <i>user+foo</i>, <i>user</i>, and

       The  <b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a></b>   parameter   controls
       whether  an  unmatched  address extension (<i>+foo</i>) is propa-
       gated to the result of table lookup.

       Besides virtual aliases, the virtual alias table can  also
       be used to implement <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domains</a>. 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
       <a href="virtual.8.html"><b>virtual</b>(8)</a>  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 <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a>. In particular,
       local <a href="aliases.5.html"><b>aliases</b>(5)</a> and local mailing lists are  not  visible
       as <i>localname@virtual-alias.domain</i>.

       Support for a <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a> looks like:

       /etc/postfix/<a href="postconf.5.html"></a>:
           <a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> = hash:/etc/postfix/virtual

       Note: some systems use <b>dbm</b> databases instead of <b>hash</b>.  See
       the output  from  "<b>postconf  -m</b>"  for  available  database

       /etc/postfix/<a href="virtual.8.html">virtual</a>:
           <i>virtual-alias.domain     anything</i> (right-hand content does not matter)
           <i>postmaster@virtual-alias.domain  postmaster</i>
           <i>user1@virtual-alias.domain       address1</i>
           <i>user2@virtual-alias.domain       address2, address3</i>

       The  <i>virtual-alias.domain anything</i> entry is required for a
       <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a>. <b>Without this entry, mail is rejected</b>
       <b>with  "relay  access  denied", or bounces with "mail loops</b>
       <b>back to myself".</b>

       Do not specify <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a> names in  the  <a href="postconf.5.html"><b></b></a>
       <b><a href="postconf.5.html#mydestination">mydestination</a></b> or <b><a href="postconf.5.html#relay_domains">relay_domains</a></b> configuration parameters.

       With  a  virtual  alias  domain,  the  Postfix SMTP server
       accepts  mail  for  <i>known-user@virtual-alias.domain</i>,   and
       rejects   mail  for  <i>unknown-user</i>@<i>virtual-alias.domain</i>  as

       Instead of specifying the virtual alias  domain  name  via
       the  <b><a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a></b> table, you may also specify it via
       the <a href="postconf.5.html"><b></a> <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a></b> configuration parameter.
       This  latter parameter uses the same syntax as the <a href="postconf.5.html"><b></b></a>
       <b><a href="postconf.5.html#mydestination">mydestination</a></b> configuration parameter.

       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 <a href="regexp_table.5.html"><b>regexp_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>.

       Each  pattern  is  a regular expression that is applied to
       the entire address being looked up. Thus, <i>user@domain</i> mail
       addresses  are  not  broken up into their <i>user</i> and <i>@domain</i>
       constituent parts, nor is <i>user+foo</i> broken up into <i>user</i> and

       Patterns  are applied in the order as specified in the ta-
       ble, until a pattern is  found  that  matches  the  search

       Results  are  the  same as with indexed file lookups, with
       the additional feature that parenthesized substrings  from
       the pattern can be interpolated as <b>$1</b>, <b>$2</b> and so on.

       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 <a href="tcp_table.5.html"><b>tcp_ta-</b></a>
       <a href="tcp_table.5.html"><b>ble</b>(5)</a>.  This feature is not available up to and including
       Postfix version 2.4.

       Each lookup operation uses the entire address once.  Thus,
       <i>user@domain</i> mail addresses are not broken  up  into  their
       <i>user</i> and <i>@domain</i> constituent parts, nor is <i>user+foo</i> broken
       up into <i>user</i> and <i>foo</i>.

       Results are the same as with indexed file lookups.

       The table format does not understand quoting  conventions.

       The  following  <a href="postconf.5.html"><b></b></a> parameters are especially relevant
       to this topic. See the Postfix  <a href="postconf.5.html"><b></b></a>  file  for  syntax
       details  and  for default values. Use the "<b>postfix reload</b>"
       command after a configuration change.

       <b><a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a></b>
              List of virtual aliasing tables.

       <b><a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a></b>
              List of <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domains</a>. This uses  the  same
              syntax as the <b><a href="postconf.5.html#mydestination">mydestination</a></b> parameter.

       <b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a></b>
              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  <b>canonical</b>,   <b>virtual</b>,   <b>alias</b>,   <b>forward</b>,
              <b>include</b>, or <b>generic</b>.

       Other parameters of interest:

       <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b>
              The  network  interface  addresses that this system
              receives mail on.  You need to stop and start Post-
              fix when this parameter changes.

       <b><a href="postconf.5.html#mydestination">mydestination</a></b>
              List  of  domains  that  this mail system considers

       <b><a href="postconf.5.html#myorigin">myorigin</a></b>
              The domain that is appended  to  any  address  that
              does not have a domain.

       <b><a href="postconf.5.html#owner_request_special">owner_request_special</a></b>
              Give special treatment to <b>owner-</b><i>xxx</i> and <i>xxx</i><b>-request</b>

       <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a></b>
              Other interfaces that this machine receives mail on
              by way of a proxy agent or network address transla-

<b>SEE ALSO</b>
       <a href="cleanup.8.html">cleanup(8)</a>, canonicalize and enqueue mail
       <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
       <a href="postconf.5.html">postconf(5)</a>, configuration parameters
       <a href="canonical.5.html">canonical(5)</a>, canonical address mapping

       <a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a>, address rewriting guide
       <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
       <a href="VIRTUAL_README.html">VIRTUAL_README</a>, domain hosting guide

       The  Secure  Mailer  license must be distributed with this

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

</pre> </body> </html>