ALIASES(5) File Formats Manual ALIASES(5)
NAME
aliases - Postfix local alias database format
SYNOPSIS
newaliases
DESCRIPTION
The aliases(5) table provides a system-wide mechanism to redirect mail for local recipients. The redirections
are processed by the Postfix local(8) delivery agent.
Normally, the aliases(5) table is specified as a text file that serves as input to the postalias(1) command.
The result, an indexed file in dbm or db format, is used for fast lookup by the mail system. Execute the com‐
mand 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 described below under "REGULAR
EXPRESSION TABLES".
Users can control delivery of their own mail by setting up .forward files in their home directory. Lines in
per-user .forward files have the same syntax as the right-hand side of aliases(5) 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-whitespace 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, delivery diagnostics are directed to that address, instead
of to the originator of the message. 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) for details of delivery to file. Delivery is not limited
to regular files. For example, to dispose of unwanted mail, deflect it to /dev/null.
|command
Mail is piped into command. Commands that contain special characters, such as whitespace, should be
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 propa‐
gated to the result of table lookup.
CASE FOLDING
The local(8) 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 expres‐
sions. For a description of regular expression lookup table syntax, see regexp_table(5) or pcre_table(5).
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 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 $1, $2
etc. substring interpolation.
SECURITY
The local(8) delivery agent disallows regular expression substitution of $1 etc. in alias_maps, because that
would open a security hole.
The local(8) delivery agent will silently ignore requests to use the proxymap(8) server within alias_maps.
Instead it will open the table directly. Before Postfix version 2.2, the local(8) delivery agent will termi‐
nate with a fatal error.
CONFIGURATION PARAMETERS
The following main.cf parameters are especially relevant. The text below provides only a parameter summary.
See postconf(5) for more details including examples.
alias_database
List of alias databases that are updated by the newaliases(1) command.
alias_maps
List of alias databases queried by the local(8) delivery agent.
allow_mail_to_commands
Restrict the usage of mail delivery to external command.
allow_mail_to_files
Restrict the usage of mail delivery to external file.
expand_owner_alias
When delivering to an alias that has an owner- companion alias, set the envelope sender address to the
right-hand side of the owner alias, instead using of the left-hand side address.
frozen_delivered_to
Update the local(8) delivery agent's Delivered-To: address (see prepend_delivered_header) only once, at
the start of a delivery; do not update the Delivered-To: address while expanding aliases or .forward
files.
STANDARDS
RFC 822 (ARPA Internet Text Messages)
SEE ALSO
local(8), local delivery agent
newaliases(1), create/update alias database
postalias(1), create/update alias database
postconf(5), 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
ALIASES(5)
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