# aliases(5) - man - phpMan [ALIASES(5)](https://www.chedong.com/phpMan.php/man/ALIASES/5/markdown) File Formats Manual [ALIASES(5)](https://www.chedong.com/phpMan.php/man/ALIASES/5/markdown) ## NAME aliases - Postfix local alias database format ## SYNOPSIS ### newaliases ## DESCRIPTION The [**aliases**(5)](https://www.chedong.com/phpMan.php/man/aliases/5/markdown) table provides a system-wide mechanism to redirect mail for local recipients. The redirections are processed by the Postfix [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery agent. Normally, the [**aliases**(5)](https://www.chedong.com/phpMan.php/man/aliases/5/markdown) table is specified as a text file that serves as input to the [**postalias**(1)](https://www.chedong.com/phpMan.php/man/postalias/1/markdown) command. The result, an indexed file in **dbm** or **db** format, is used for fast lookup by the mail system. Execute the command **newaliases** 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 de‐ scribed below under "REGULAR EXPRESSION TABLES". Users can control delivery of their own mail by setting up **.forward** files in their home di‐ rectory. Lines in per-user **.forward** files have the same syntax as the right-hand side of [**aliases**(5)](https://www.chedong.com/phpMan.php/man/aliases/5/markdown) entries. The format of the alias database input file is as follows: • An alias definition has the form _name_: _value1_, _value2_, _..._ • Empty lines and whitespace-only lines are ignored, as are lines whose first non-white‐ space character is a `#'. • A logical line starts with non-whitespace text. A line that starts with whitespace continues a logical line. The _name_ is a local address (no domain part). Use double quotes when the name contains any special characters such as whitespace, `#', `:', or `@'. The _name_ is folded to lowercase, in order to make database lookups case insensitive. In addition, when an alias exists for **owner-**_name_, this will override the envelope sender ad‐ dress, so that delivery diagnostics are directed to **owner-**_name_, instead of the originator of the message (for details, see **owner**___**request**___**special**, **expand**___**owner**___**alias** and **re**‐‐ **set**___**owner**___**alias**). This is typically used to direct delivery errors to the maintainer 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 _value_ contains one or more of the following: _address_ Mail is forwarded to _address_, which is compatible with the RFC 822 standard. _/file/name_ Mail is appended to _/file/name_. See [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) for details of delivery to file. Deliv‐ ery is not limited to regular files. For example, to dispose of unwanted mail, de‐ flect it to **/dev/null**. |_command_ Mail is piped into _command_. Commands that contain special characters, such as white‐ space, should be enclosed between double quotes. See [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) for details of delivery to command. When the command fails, a limited amount of command output is mailed back to the sender. The file **/usr/include/sysexits.h** defines the expected exit status codes. For example, use **"|exit** **67"** to simulate a "user unknown" error, and **"|exit** **0"** to implement an expensive black hole. **:include:**_/file/name_ Mail is sent to the destinations listed in the named file. Lines in **:include:** 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 "|_command_" and _/file/name_ is disallowed by default. To enable, edit the **allow**___**mail**___**to**___**commands** and **allow**___**mail**___**to**___**files** configuration parameters. ## ADDRESS EXTENSION When alias database search fails, and the recipient localpart contains the optional recipient delimiter (e.g., _user+foo_), the search is repeated for the unextended address (e.g., _user_). The **propagate**___**unmatched**___**extensions** parameter controls whether an unmatched address extension (_+foo_) is propagated to the result of table lookup. ## CASE FOLDING The [local(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery agent always folds the search string to lowercase before database lookup. ## 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 **reg**‐‐ **exp**___**[table**(5)](https://www.chedong.com/phpMan.php/man/table/5/markdown) or **pcre**___**[table**(5)](https://www.chedong.com/phpMan.php/man/table/5/markdown). 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 _user+foo_ is not broken up into _user_ and _foo_. Regular expressions are applied in the order as specified in the table, until a regular ex‐ pression 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 **$1**, **$2** etc. substring interpolation. ## SECURITY The [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery agent disallows regular expression substitution of $1 etc. in **alias**___**maps**, because that would open a security hole. The [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery agent will silently ignore requests to use the [**proxymap**(8)](https://www.chedong.com/phpMan.php/man/proxymap/8/markdown) server within **alias**___**maps**. Instead it will open the table directly. Before Postfix version 2.2, the [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery agent will terminate with a fatal error. ## CONFIGURATION PARAMETERS The following **main.cf** parameters are especially relevant. The text below provides only a pa‐ rameter summary. See [**postconf**(5)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown) for more details including examples. **alias**___**database** **(see** **'postconf** **-d'** **output)** The alias databases for [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery that are updated with "**newaliases**" or with "**sendmail** **-bi**". **alias**___**maps** **(see** **'postconf** **-d'** **output)** The alias databases that are used for [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery. **allow**___**mail**___**to**___**commands** **(alias,** **forward)** Restrict [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) mail delivery to external commands. **allow**___**mail**___**to**___**files** **(alias,** **forward)** Restrict [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) mail delivery to external files. **expand**___**owner**___**alias** **(no)** When delivering to an alias "_aliasname_" that has an "owner-_aliasname_" companion alias, set the envelope sender address to the expansion of the "owner-_aliasname_" alias. **propagate**___**unmatched**___**extensions** **(canonical,** **virtual)** What address lookup tables copy an address extension from the lookup key to the lookup result. **owner**___**request**___**special** **(yes)** Enable special treatment for owner-_listname_ entries in the [**aliases**(5)](https://www.chedong.com/phpMan.php/man/aliases/5/markdown) file, and don't split owner-_listname_ and _listname_-request address localparts when the recipient_delim‐ iter is set to "-". **recipient**___**delimiter** **(empty)** The set of characters that can separate a user name from its extension (example: user+foo), or a .forward file name from its extension (example: .forward+foo). Available in Postfix version 2.3 and later: **frozen**___**delivered**___**to** **(yes)** Update the [**local**(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown) delivery agent's idea of the Delivered-To: address (see prepend_delivered_header) only once, at the start of a delivery attempt; do not update the Delivered-To: address while expanding aliases or .forward files. ## STANDARDS RFC 822 (ARPA Internet Text Messages) ## SEE ALSO [local(8)](https://www.chedong.com/phpMan.php/man/local/8/markdown), local delivery agent [newaliases(1)](https://www.chedong.com/phpMan.php/man/newaliases/1/markdown), create/update alias database [postalias(1)](https://www.chedong.com/phpMan.php/man/postalias/1/markdown), create/update alias database [postconf(5)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown), configuration parameters ## README FILES Use "**postconf** **readme**___**directory**" or "**postconf** **html**___**directory**" to locate this information. DATABASE_README, Postfix lookup table overview ## 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 Wietse Venema Google, Inc. 111 8th Avenue New York, NY 10011, USA [ALIASES(5)](https://www.chedong.com/phpMan.php/man/ALIASES/5/markdown)