xref: /netbsd-src/external/ibm-public/postfix/dist/html/aliases.5.html (revision e6c7e151de239c49d2e38720a061ed9d1fa99309)
1<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
2        "http://www.w3.org/TR/html4/loose.dtd">
3<html> <head>
4<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
5<title> Postfix manual - aliases(5) </title>
6</head> <body> <pre>
7ALIASES(5)                                                          ALIASES(5)
8
9<b>NAME</b>
10       aliases - Postfix local alias database format
11
12<b>SYNOPSIS</b>
13       <b>newaliases</b>
14
15<b>DESCRIPTION</b>
16       The  <a href="aliases.5.html"><b>aliases</b>(5)</a> table provides a system-wide mechanism to redirect mail
17       for local recipients. The redirections are  processed  by  the  Postfix
18       <a href="local.8.html"><b>local</b>(8)</a> delivery agent.
19
20       Normally,  the <a href="aliases.5.html"><b>aliases</b>(5)</a> table is specified as a text file that serves
21       as input to the <a href="postalias.1.html"><b>postalias</b>(1)</a> command. The result, an  indexed  file  in
22       <b>dbm</b>  or  <b>db</b> format, is used for fast lookup by the mail system. Execute
23       the command <b>newaliases</b> in order  to  rebuild  the  indexed  file  after
24       changing the Postfix alias database.
25
26       When  the  table  is provided via other means such as NIS, LDAP or SQL,
27       the same lookups are done as for ordinary indexed files.
28
29       Alternatively, the table can be provided as  a  regular-expression  map
30       where  patterns  are  given  as  regular expressions. In this case, the
31       lookups are done in a slightly different way as described  below  under
32       "REGULAR EXPRESSION TABLES".
33
34       Users  can  control  delivery  of their own mail by setting up <b>.forward</b>
35       files in their home directory.  Lines in per-user <b>.forward</b>  files  have
36       the same syntax as the right-hand side of <a href="aliases.5.html"><b>aliases</b>(5)</a> entries.
37
38       The format of the alias database input file is as follows:
39
40       <b>o</b>      An alias definition has the form
41
42                   <i>name</i>: <i>value1</i>, <i>value2</i>, <i>...</i>
43
44       <b>o</b>      Empty  lines and whitespace-only lines are ignored, as are lines
45              whose first non-whitespace character is a `#'.
46
47       <b>o</b>      A logical line starts with  non-whitespace  text.  A  line  that
48              starts with whitespace continues a logical line.
49
50       The  <i>name</i>  is a local address (no domain part).  Use double quotes when
51       the name contains any special characters such as whitespace, `#',  `:',
52       or  `@'.  The  <i>name</i>  is  folded to lowercase, in order to make database
53       lookups case insensitive.
54
55       In addition, when an alias exists for <b>owner-</b><i>name</i>,  this  will  override
56       the  envelope sender address, so that delivery diagnostics are directed
57       to <b>owner-</b><i>name</i>, instead of the originator of the message  (for  details,
58       see  <b><a href="postconf.5.html#owner_request_special">owner_request_special</a></b>,  <b><a href="postconf.5.html#expand_owner_alias">expand_owner_alias</a></b> and <b><a href="postconf.5.html#reset_owner_alias">reset_owner_alias</a></b>).
59       This is typically used to direct delivery errors to the maintainer of a
60       mailing  list,  who  is  in a better position to deal with mailing list
61       delivery problems than the originator of the undelivered mail.
62
63       The <i>value</i> contains one or more of the following:
64
65       <i>address</i>
66              Mail is forwarded to <i>address</i>, which is compatible with  the  <a href="http://tools.ietf.org/html/rfc822">RFC</a>
67              <a href="http://tools.ietf.org/html/rfc822">822</a> standard.
68
69       <i>/file/name</i>
70              Mail  is  appended  to  <i>/file/name</i>.  See <a href="local.8.html"><b>local</b>(8)</a> for details of
71              delivery to file.  Delivery is not  limited  to  regular  files.
72              For  example,  to  dispose  of  unwanted  mail,  deflect  it  to
73              <b>/dev/null</b>.
74
75       |<i>command</i>
76              Mail is piped into <i>command</i>. Commands that contain special  char-
77              acters,  such  as  whitespace, should be enclosed between double
78              quotes. See <a href="local.8.html"><b>local</b>(8)</a> for details of delivery to command.
79
80              When the command fails, a limited amount of  command  output  is
81              mailed  back  to  the  sender.  The file <b>/usr/include/sysexits.h</b>
82              defines the expected exit status codes. For example, use  <b>"|exit</b>
83              <b>67"</b>  to simulate a "user unknown" error, and <b>"|exit 0"</b> to imple-
84              ment an expensive black hole.
85
86       <b>:include:</b><i>/file/name</i>
87              Mail is sent to the  destinations  listed  in  the  named  file.
88              Lines  in <b>:include:</b> files have the same syntax as the right-hand
89              side of alias entries.
90
91              A destination can be any destination that is described  in  this
92              manual  page.  However, delivery to "|<i>command</i>" and <i>/file/name</i> is
93              disallowed by default. To enable,  edit  the  <b><a href="postconf.5.html#allow_mail_to_commands">allow_mail_to_com</a>-</b>
94              <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.
95
96<b>ADDRESS EXTENSION</b>
97       When  alias database search fails, and the recipient localpart contains
98       the optional  recipient  delimiter  (e.g.,  <i>user+foo</i>),  the  search  is
99       repeated for the unextended address (e.g., <i>user</i>).
100
101       The   <b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a></b>   parameter  controls  whether  an
102       unmatched address extension (<i>+foo</i>) is propagated to the result of table
103       lookup.
104
105<b>CASE FOLDING</b>
106       The <a href="local.8.html">local(8)</a> delivery agent always folds the search string to lowercase
107       before database lookup.
108
109<b>REGULAR EXPRESSION TABLES</b>
110       This section describes how the table lookups change when the  table  is
111       given  in the form of regular expressions. For a description of regular
112       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>.
113       NOTE: these formats do not use ":" at the end of a pattern.
114
115       Each regular expression is applied to the entire search string. Thus, a
116       search string <i>user+foo</i> is not broken up into <i>user</i> and <i>foo</i>.
117
118       Regular expressions are applied in the order as specified in the table,
119       until a regular expression is found that matches the search string.
120
121       Lookup results are the same as with indexed file lookups.  For security
122       reasons there is no support for <b>$1</b>, <b>$2</b> etc. substring interpolation.
123
124<b>SECURITY</b>
125       The <a href="local.8.html"><b>local</b>(8)</a> delivery agent disallows regular  expression  substitution
126       of $1 etc. in <b><a href="postconf.5.html#alias_maps">alias_maps</a></b>, because that would open a security hole.
127
128       The  <a href="local.8.html"><b>local</b>(8)</a>  delivery  agent will silently ignore requests to use the
129       <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
130       directly.  Before Postfix version 2.2, the <a href="local.8.html"><b>local</b>(8)</a> delivery agent will
131       terminate with a fatal error.
132
133<b>CONFIGURATION PARAMETERS</b>
134       The following <a href="postconf.5.html"><b>main.cf</b></a> parameters are  especially  relevant.   The  text
135       below  provides  only  a  parameter  summary.  See <a href="postconf.5.html"><b>postconf</b>(5)</a> for more
136       details including examples.
137
138       <b><a href="postconf.5.html#alias_database">alias_database</a> (see 'postconf -d' output)</b>
139              The alias databases for <a href="local.8.html"><b>local</b>(8)</a> delivery that are updated  with
140              "<b>newaliases</b>" or with "<b>sendmail -bi</b>".
141
142       <b><a href="postconf.5.html#alias_maps">alias_maps</a> (see 'postconf -d' output)</b>
143              The alias databases that are used for <a href="local.8.html"><b>local</b>(8)</a> delivery.
144
145       <b><a href="postconf.5.html#allow_mail_to_commands">allow_mail_to_commands</a> (alias, forward)</b>
146              Restrict <a href="local.8.html"><b>local</b>(8)</a> mail delivery to external commands.
147
148       <b><a href="postconf.5.html#allow_mail_to_files">allow_mail_to_files</a> (alias, forward)</b>
149              Restrict <a href="local.8.html"><b>local</b>(8)</a> mail delivery to external files.
150
151       <b><a href="postconf.5.html#expand_owner_alias">expand_owner_alias</a> (no)</b>
152              When   delivering   to   an   alias   "<i>aliasname</i>"  that  has  an
153              "owner-<i>aliasname</i>"  companion  alias,  set  the  envelope  sender
154              address to the expansion of the "owner-<i>aliasname</i>" alias.
155
156       <b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a> (canonical, virtual)</b>
157              What  address  lookup  tables copy an address extension from the
158              lookup key to the lookup result.
159
160       <b><a href="postconf.5.html#owner_request_special">owner_request_special</a> (yes)</b>
161              Enable special  treatment  for  owner-<i>listname</i>  entries  in  the
162              <a href="aliases.5.html"><b>aliases</b>(5)</a>  file,  and  don't  split  owner-<i>listname</i>  and  <i>list-</i>
163              <i>name</i>-request address localparts when the <a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a>  is
164              set to "-".
165
166       <b><a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> (empty)</b>
167              The  set  of  characters  that can separate a user name from its
168              extension (example: user+foo), or a .forward file name from  its
169              extension (example: .forward+foo).
170
171       Available in Postfix version 2.3 and later:
172
173       <b><a href="postconf.5.html#frozen_delivered_to">frozen_delivered_to</a> (yes)</b>
174              Update  the  <a href="local.8.html"><b>local</b>(8)</a> delivery agent's idea of the Delivered-To:
175              address (see <a href="postconf.5.html#prepend_delivered_header">prepend_delivered_header</a>) only once, at  the  start
176              of  a  delivery attempt; do not update the Delivered-To: address
177              while expanding aliases or .forward files.
178
179<b>STANDARDS</b>
180       <a href="http://tools.ietf.org/html/rfc822">RFC 822</a> (ARPA Internet Text Messages)
181
182<b>SEE ALSO</b>
183       <a href="local.8.html">local(8)</a>, local delivery agent
184       <a href="newaliases.1.html">newaliases(1)</a>, create/update alias database
185       <a href="postalias.1.html">postalias(1)</a>, create/update alias database
186       <a href="postconf.5.html">postconf(5)</a>, configuration parameters
187
188<b>README FILES</b>
189       <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
190
191<b>LICENSE</b>
192       The Secure Mailer license must be distributed with this software.
193
194<b>AUTHOR(S)</b>
195       Wietse Venema
196       IBM T.J. Watson Research
197       P.O. Box 704
198       Yorktown Heights, NY 10598, USA
199
200       Wietse Venema
201       Google, Inc.
202       111 8th Avenue
203       New York, NY 10011, USA
204
205                                                                    ALIASES(5)
206</pre> </body> </html>
207