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ALIASES(5) ALIASES(5)
<b>NAME</b>
aliases - Postfix local alias database format
<b>SYNOPSIS</b>
<b>newaliases</b>
<b>DESCRIPTION</b>
The <a href="aliases.5.html"><b>aliases</b>(5)</a> table provides a system-wide mechanism to redirect mail
for local recipients. The redirections are processed by the Postfix
<a href="local.8.html"><b>local</b>(8)</a> delivery agent.
Normally, the <a href="aliases.5.html"><b>aliases</b>(5)</a> table is specified as a text file that serves
as input to the <a href="postalias.1.html"><b>postalias</b>(1)</a> command. The result, an indexed file in
<b>dbm</b> or <b>db</b> format, is used for fast lookup by the mail system. Execute
the command <b>newaliases</b> in order to rebuild the indexed file after
changing the Postfix alias database.
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 expressions. In this case, the
lookups are done in a slightly different way as described below under
"REGULAR EXPRESSION TABLES".
Users can control delivery of their own mail by setting up <b>.forward</b>
files in their home directory. Lines in per-user <b>.forward</b> files have
the same syntax as the right-hand side of <a href="aliases.5.html"><b>aliases</b>(5)</a> entries.
The format of the alias database input file is as follows:
<b>o</b> An alias definition has the form
<i>name</i>: <i>value1</i>, <i>value2</i>, <i>...</i>
<b>o</b> Empty lines and whitespace-only lines are ignored, as are lines
whose first non-whitespace character is a `#'.
<b>o</b> A logical line starts with non-whitespace text. A line that
starts with whitespace continues a logical line.
The <i>name</i> is a local address (no domain part). Use double quotes when
the name contains any special characters such as whitespace, `#', `:',
or `@'. The <i>name</i> is folded to lowercase, in order to make database
lookups case insensitive.
In addition, when an alias exists for <b>owner-</b><i>name</i>, delivery diagnostics
are directed to that address, instead of to the originator of the mes-
sage. This is typically used to direct delivery errors to the main-
tainer of a mailing list, who is in a better position to deal with
mailing list delivery problems than the originator of the undelivered
mail.
The <i>value</i> contains one or more of the following:
<i>address</i>
Mail is forwarded to <i>address</i>, which is compatible with the <a href="http://tools.ietf.org/html/rfc822">RFC</a>
<a href="http://tools.ietf.org/html/rfc822">822</a> standard.
<i>/file/name</i>
Mail is appended to <i>/file/name</i>. See <a href="local.8.html"><b>local</b>(8)</a> for details of
delivery to file. Delivery is not limited to regular files.
For example, to dispose of unwanted mail, deflect it to
<b>/dev/null</b>.
|<i>command</i>
Mail is piped into <i>command</i>. Commands that contain special char-
acters, such as whitespace, should be enclosed between double
quotes. See <a href="local.8.html"><b>local</b>(8)</a> for details of delivery to command.
When the command fails, a limited amount of command output is
mailed back to the sender. The file <b>/usr/include/sysexits.h</b>
defines the expected exit status codes. For example, use <b>"|exit</b>
<b>67"</b> to simulate a "user unknown" error, and <b>"|exit 0"</b> to imple-
ment an expensive black hole.
<b>:include:</b><i>/file/name</i>
Mail is sent to the destinations listed in the named file.
Lines in <b>:include:</b> files have the same syntax as the right-hand
side of alias entries.
A destination can be any destination that is described in this
manual page. However, delivery to "|<i>command</i>" and <i>/file/name</i> is
disallowed by default. To enable, edit the <b><a href="postconf.5.html#allow_mail_to_commands">allow_mail_to_com</a>-</b>
<b><a href="postconf.5.html#allow_mail_to_commands">mands</a></b> and <b><a href="postconf.5.html#allow_mail_to_files">allow_mail_to_files</a></b> configuration parameters.
<b>ADDRESS EXTENSION</b>
When alias database search fails, and the recipient localpart contains
the optional recipient delimiter (e.g., <i>user+foo</i>), the search is
repeated for the unextended address (e.g., <i>user</i>).
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 propagated to the result of table
lookup.
<b>CASE FOLDING</b>
The <a href="local.8.html">local(8)</a> delivery agent always folds the search string to lowercase
before database lookup.
<b>REGULAR EXPRESSION 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_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>.
NOTE: these formats do not use ":" at the end of a pattern.
Each regular expression is applied to the entire search string. Thus, a
search string <i>user+foo</i> is not broken up into <i>user</i> and <i>foo</i>.
Regular expressions are applied in the order as specified in the table,
until a regular expression is found that matches the search string.
Lookup results are the same as with indexed file lookups. For security
reasons there is no support for <b>$1</b>, <b>$2</b> etc. substring interpolation.
<b>SECURITY</b>
The <a href="local.8.html"><b>local</b>(8)</a> delivery agent disallows regular expression substitution
of $1 etc. in <b><a href="postconf.5.html#alias_maps">alias_maps</a></b>, because that would open a security hole.
The <a href="local.8.html"><b>local</b>(8)</a> delivery agent will silently ignore requests to use the
<a href="proxymap.8.html"><b>proxymap</b>(8)</a> server within <b><a href="postconf.5.html#alias_maps">alias_maps</a></b>. Instead it will open the table
directly. Before Postfix version 2.2, the <a href="local.8.html"><b>local</b>(8)</a> delivery agent will
terminate with a fatal error.
<b>CONFIGURATION PARAMETERS</b>
The following <a href="postconf.5.html"><b>main.cf</b></a> parameters are especially relevant. The text
below provides only a parameter summary. See <a href="postconf.5.html"><b>postconf</b>(5)</a> for more
details including examples.
<b><a href="postconf.5.html#alias_database">alias_database</a></b>
List of alias databases that are updated by the <a href="newaliases.1.html"><b>newaliases</b>(1)</a>
command.
<b><a href="postconf.5.html#alias_maps">alias_maps</a></b>
List of alias databases queried by the <a href="local.8.html"><b>local</b>(8)</a> delivery agent.
<b><a href="postconf.5.html#allow_mail_to_commands">allow_mail_to_commands</a></b>
Restrict the usage of mail delivery to external command.
<b><a href="postconf.5.html#allow_mail_to_files">allow_mail_to_files</a></b>
Restrict the usage of mail delivery to external file.
<b><a href="postconf.5.html#expand_owner_alias">expand_owner_alias</a></b>
When delivering to an alias that has an <b>owner-</b> companion alias,
set the envelope sender address to the right-hand side of the
owner alias, instead using of the left-hand side address.
<b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a></b>
A list of address rewriting or forwarding mechanisms that propa-
gate 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>for-</b>
<b>ward</b>, <b>include</b>, or <b>generic</b>.
<b><a href="postconf.5.html#owner_request_special">owner_request_special</a></b>
Give special treatment to <b>owner-</b><i>listname</i> and <i>listname</i><b>-request</b>
addresses.
<b><a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a></b>
Delimiter that separates recipients from address extensions.
Available in Postfix version 2.3 and later:
<b><a href="postconf.5.html#frozen_delivered_to">frozen_delivered_to</a></b>
Update the <a href="local.8.html">local(8)</a> delivery agent's Delivered-To: address (see
<a href="postconf.5.html#prepend_delivered_header">prepend_delivered_header</a>) only once, at the start of a delivery;
do not update the Delivered-To: address while expanding aliases
or .forward files.
<b>STANDARDS</b>
<a href="http://tools.ietf.org/html/rfc822">RFC 822</a> (ARPA Internet Text Messages)
<b>SEE ALSO</b>
<a href="local.8.html">local(8)</a>, local delivery agent
<a href="newaliases.1.html">newaliases(1)</a>, create/update alias database
<a href="postalias.1.html">postalias(1)</a>, create/update alias database
<a href="postconf.5.html">postconf(5)</a>, configuration parameters
<b>README FILES</b>
<a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
<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
Wietse Venema
Google, Inc.
111 8th Avenue
New York, NY 10011, USA
ALIASES(5)
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