NetBSD/gnu/dist/postfix/html/virtual.5.html

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VIRTUAL(5) VIRTUAL(5)
<b>NAME</b>
virtual - format of Postfix virtual table
<b>SYNOPSIS</b>
<b>postmap</b> <b>/etc/postfix/virtual</b>
<b>DESCRIPTION</b>
The optional <b>virtual</b> table specifies address redirections
for local and non-local recipients or domains. The redi-
rections are used by the <a href="cleanup.8.html"><b>cleanup</b>(8)</a> daemon. The redirec-
tions are recursive.
The <b>virtual</b> redirection is applied only to recipient enve-
lope addresses, and does not affect message headers.
Think Sendmail rule set <b>S0</b>, if you like. Use <a href="canonical.5.html"><b>canonical</b>(5)</a>
mapping to rewrite header and envelope addresses in gen-
eral.
Normally, the <b>virtual</b> 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</b> <b>/etc/postfix/virtual</b> 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.
<b>POSTFIX-STYLE</b> <b>VIRTUAL</b> <b>DOMAINS</b>
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 <a href="aliases.5.html"><b>aliases</b>(5)</a> and mailing lists
are not visible as <i>localname@virtual.domain</i>.
Use a Sendmail-style virtual domain (see below) if local
usernames, <a href="aliases.5.html"><b>aliases</b>(5)</a> or mailing lists should be visible
as <i>localname@virtual.domain</i>.
Support for a Postfix-style virtual domain looks like:
/etc/postfix/virtual:
<i>virtual.domain</i> <i>anything</i> (right-hand content does not matter)
<i>postmaster@virtual.domain</i> <i>postmaster</i>
<i>user1@virtual.domain</i> <i>address1</i>
<i>user2@virtual.domain</i> <i>address2,</i> <i>address3</i>
The <i>virtual.domain</i> <i>anything</i> entry is required for a Post-
fix-style virtual domain.
Do not list a Postfix-style virtual domain in the <b>main.cf</b>
<b>mydestination</b> 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 <i>known-user@virtual.domain</i> and
rejects mail for <i>unknown-user</i>@<i>virtual.domain</i> as undeliver-
able.
<b>SENDMAIL-STYLE</b> <b>VIRTUAL</b> <b>DOMAINS</b>
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 <i>localname@virtual.domain</i>.
Use a Postfix-style virtual domain (see above) if local
usernames, <a href="aliases.5.html"><b>aliases</b>(5)</a> or mailing lists should not be visi-
ble as <i>localname@virtual.domain</i>.
Support for a Sendmail-style virtual domain looks like:
/etc/postfix/main.cf:
mydestination = $myhostname localhost.$mydomain $mydomain
<i>virtual.domain</i>
/etc/postfix/virtual:
<i>user1@virtual.domain</i> <i>address1</i>
<i>user2@virtual.domain</i> <i>address2,</i> <i>address3</i>
The <b>main.cf</b> <b>mydestination</b> entry is required for a Send-
mail-style virtual domain.
Do not specify a <i>virtual.domain</i> <i>anything</i> 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 <i>user</i>@<i>vir-</i>
<i>tual.domain</i> 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.
<b>TABLE</b> <b>FORMAT</b>
The format of the virtual table is as follows, mappings
being tried in the order as listed in this manual page:
<i>pattern</i> <i>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</i> <i>address,</i> <i>address,</i> <i>...</i>
Mail for <i>user</i>@<i>domain</i> is redirected to <i>address</i>.
This form has the highest precedence.
<i>user</i> <i>address,</i> <i>address,</i> <i>...</i>
Mail for <i>user</i>@<i>site</i> is redirected to <i>address</i> when
<i>site</i> is equal to $<b>myorigin</b>, when <i>site</i> is listed in
$mydestination, or when it is listed in
$<i>inet_interfaces</i>.
This functionality overlaps with functionality of
the local <i>alias</i>(5) database. The difference is that
<b>virtual</b> mapping can be applied to non-local
addresses.
@<i>domain</i> <i>address,</i> <i>address,</i> <i>...</i>
Mail for any user in <i>domain</i> is redirected to
<i>address</i>. This form has the lowest precedence.
In all the above forms, when <i>address</i> has the form @<i>other-</i>
<i>domain</i>, the result is the same user in <i>otherdomain</i>. This
works for the first address in the expansion only.
<b>ADDRESS</b> <b>EXTENSION</b>
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
@<i>domain</i>. An unmatched address extension (<i>+foo</i>) is propa-
gated to the result of table lookup.
<b>REGULAR</b> <b>EXPRESSION</b> <b>TABLES</b>
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</b><i>_</i><b>table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre</b><i>_</i><b>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
<i>foo</i>.
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 <b>$1</b>, <b>$2</b> and so on.
<b>BUGS</b>
The table format does not understand quoting conventions.
<b>CONFIGURATION</b> <b>PARAMETERS</b>
The following <b>main.cf</b> parameters are especially relevant
to this topic. See the Postfix <b>main.cf</b> file for syntax
details and for default values. Use the <b>postfix</b> <b>reload</b>
command after a configuration change.
<b>virtual</b><i>_</i><b>maps</b>
List of virtual mapping tables.
Other parameters of interest:
<b>inet</b><i>_</i><b>interfaces</b>
The network interface addresses that this system
receives mail on.
<b>mydestination</b>
List of domains that this mail system considers
local.
<b>myorigin</b>
The domain that is appended to locally-posted mail.
<b>owner</b><i>_</i><b>request</b><i>_</i><b>special</b>
Give special treatment to <b>owner-</b><i>xxx</i> and <i>xxx</i><b>-request</b>
addresses.
<b>SEE</b> <b>ALSO</b>
<a href="cleanup.8.html">cleanup(8)</a> canonicalize and enqueue mail
<a href="postmap.1.html">postmap(1)</a> create mapping table
<a href="pcre_table.5.html">pcre_table(5)</a> format of PCRE tables
<a href="regexp_table.5.html">regexp_table(5)</a> format of POSIX regular expression tables
<b>LICENSE</b>
The Secure Mailer license must be distributed with this
software.
<b>AUTHOR(S)</b>
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
1
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