Special address formats for list members

There are a few special address formats that may be worth considering using for list members, or that users may wish to use if subscribing themselves to a mailing list.

For one thing, it may be worth considering subscribing using a subaddress, to aid in convenient processing, e.g., by a Sieve filter, of the mailing list postings when they are received. Such Sieve filter processing might include automatically filing mailing list postings into a special folder based on the  subaddress  present on the recipient address, or specialized processing if one is the list moderator; see examples in Moderated mailing lists.

On a list member address, for MTA mailing lists defined via alias options, the alias file or alias database, a comment string containing the special string  (by default " ") defined by the   MTA option disables the ability for the list member to post: the list member can receive list messages, but may not post. Using this comment string on every list member would be one way (though not necessarily the simplest way -- see Restricting posting access to large lists) to set up a broadcast-only (no posting) mailing list.

On a list member address, for MTA mailing lists defined via alias options, the alias file or alias database, a comment string containing the special string (by default " ") defined by the   MTA option disables the ability for the list member to receive list postings: the list member  might be able to make list postings (depending upon any relevant mailing list access  controls), but will not receive list postings. In particular, a list moderator may wish to use this feature -- the list moderator will see the list messages initially during the moderation phase, and may not wish to receive the messages again when the actual posting goes through.

For aliases defined via user LDAP entries, note that as of MS 7.0.5 a  (or whatever LDAP attribute is named by the   MTA option) value of   is considered valid, but will not receive any messages (messages are discarded). This is not suitable for the normal moderator use mentioned above as such a user entry receives no mail, but it is suitable for unmonitored mailboxes, when it is not intended that the mailbox should ever receive any messages. And it may be suitable for cases where mail forwarding or application of a user Sieve filter is desired  (but normal receipt of messages is not desired).

(New in MS 8.0.1.) On a list member address, a comment string containing the special string (by default  " ") defined by the   MTA option will cause the address specified in that comment string to be used as an alternate delivery address, for messages which cannot be delivered to this primary list member address.

See also:
 * Subaddresses in aliases
 * Sieve filters
 * fileinto Option
 * Sieve subaddress extension
 * Moderated mailing lists
 * post_off MTA Option
 * mail_off MTA Option
 * alternate_recipient MTA Option
 * Alias options
 * Alias file
 * Alias database
 * Restricting posting access to large lists
 * Mailing lists