Chapter 13. Mailing Lists and ~/.forward

A mailing list is the name of a single recipient^[1] that, when expanded by sendmail aliasing, becomes a list of many recipients. Mailing lists can be internal (in which all recipients are listed in the aliases file), external (in which all recipients are listed in external files), or a combination of the two. The list of recipients that forms a mailing list can include users, programs, and files.

^[1] RFC defines a mailing list as a pseudouser's address that expands to multiple real email addresses. As you should recall, with the ~/.forward file, real email addresses also can expand to mailing lists.