|ALIASES(5)||File Formats Manual||ALIASES(5)|
aliases — aliases
file for smtpd
This manual page describes the format of the
aliases file, as used by
smtpd(8). An alias in its simplest
form is used to assign an arbitrary name to an email address, or a group of
email addresses. This provides a convenient way to send mail. For example an
alias could refer to all users of a group: email to that alias would be sent
to all members of the group. Much more complex aliases can be defined
however: an alias can refer to other aliases, be used to send mail to a file
instead of another person, or to execute various commands.
Within the file, ‘
#’ is a
comment delimiter; anything placed after it is discarded. The file consists
of key/value mappings of the form:
key is always folded to lowercase before alias lookups to ensure that there can be no ambiguity. The key is expanded to the corresponding values, which consist of one or more of the following:
- A user on the host machine. The user must have a valid entry in the passwd(5) database file.
- Append messages to file, specified by its absolute pathname.
- Pipe the message to command on its standard input. The command is run under the privileges of the daemon's unprivileged account.
- Include any definitions in file as alias entries. The format of the file is identical to this one.
- An email address in RFC 5322 format. If an address extension is appended to the user-part, it is first compared for an exact match. It is then stripped so that an address such as firstname.lastname@example.org will only use the part that precedes ‘+’ as a key.
- error:code message
- A status code and message to return. The code must be 3 digits, starting 4XX (TempFail) or 5XX (PermFail). The message must be present and can be freely chosen.
aliases file format appeared in
|April 23, 2020||Linux 5.17.4-arch1-1|