At small sites that just use mailing lists internally, the problems are few and can be easily solved locally. But as lists get to be large (more than a few hundred recipients), many (more than 50 lists), or complex (using exploders), problems become harder to localize and more difficult to solve. In the following discussion we present the most common problems. It is by no means comprehensive, but it should provide information to solve most problems.
The eventual recipient of a
mailing-list message should be able to reply to the message and have
that reply go to either the original sender or the list as a whole.
Which happens is an administrative decision. In general, replies go
to the address listed in the
Reply-To: headers. If the intention is to have
replies go to the list as a whole, these headers need to be rewritten
by a filter at the originating site:
list: "|/etc/local/mailfilter list -oi -odq -flist-request list-real"
Here, the name of the filter has replaced sendmail in the aliases file entry. Writing such a filter is complex. The original addresses need to be preserved with appropriate headers before they are rewritten by the filter.
The converse problem is that not all mail-handling programs handle
replies properly. Some programs, such as UUCP and certain versions of
emacs-mail, insist on replying to the envelope
sender as conveyed in the five-character
From " header. By setting up lists correctly (as we showed earlier), ...