The MTA has flexible mailing list facilities, and facilities for performing automated processing of certain (typically mailing list related) messages.
In the MTA, mailing lists are implemented as a special form of MTA alias: controlling mailing list headers, access to post to mailing lists, setting up moderated mailing lists, etc., are controlled via the alias that defines the mailing list. Alias features fundamental to mailing list definitions include:
- Overriding the original envelope From address of each posting with the list "owner" address,
- A variety of flexible ways to specify the addresses of list members,
And further there are optional alias features that may be of particular interest on mailing list definitions, including:
- Size limits on posted messages,
Posting restrictions (who may post to the list address), with many variants including:
- Permission to post restricted to list members,
- Permission to post requires authenticated message submission,
- Permission to post granted to certain source domains,
- Certain users or domains "black-listed" from posting,
- Moderated lists (posting attempts require moderator review and approval),
- List-specific password required to post,
- Deferred expansion (i.e., "offline" expansion) of list membership,
- Application of a list-specific Sieve filter to attempted list postings,
- Addition of list-specific header lines,
- List-specific removal of header lines,
- "Tagging" of the Subject: header line of postings,
- Addition of prefix text or suffix text (e.g., a "disclaimer") to list postings,
- List-specific conversion tag, possibly to trigger list-specific conversion operations on list postings,
- List-specific "opt in" to spam/virus filtering,
See Aliases for background general information on aliases and their various implementation mechanisms, including Direct LDAP aliases, Unified Configuration alias options, the MTA alias file, and the (optional) MTA alias database. Details specifically on mailing list membership definitions, with their many options and variations, are described in Mailing list addresses.
See Mass mailings for a discussion of topics of particular interest in the case of sending announcements or emergency communications to very large numbers of users.