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 command newaliases in order to rebuild the indexed file after changing the Postfix alias database. The input and output file formats are expected to be compatible with Sendmail version 8, and are expected to be suitable for the use as NIS maps. 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 enclosed between double quotes. See local(8) 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.