Re: [Exim] Exim in a one-domain, multiple-site configuration

On exim-users porl@??? wrote:
>At the next full hour, site 1 dials into site 2, and site 2 gets the
>email in the mailbox "site-b". When exim receives said message, it
>delivers it to the local user "fritz", BUT: since the headers of
>the mail have not changed, it ALSO gets delivered to the Box
>"site-a".

Fetchmail is unfortunately not designed or useful for multi-user
operation (or else I misread a lot of documentation).

The reason is that most header lines, is our case especially
From:, To: and Cc:, are merely indicative and do not have any
strict relation to where the mail goes or to where errors should
be returned.

With your setup, I'm surprised you don't have more problems.
Think about Bcc where the recipient's name does not even appear
in the headers. Think about mailing lists, where not only the
recipient does not appear, but the errors should not go to the
From, and sending things on to the To would cause planetary mail
loops.

It seems you escape this because your external mail is already
separated between your two sites.

As for solving the problem, you want to keep the Return-Path and
the real user ids to which the mail is delivered.

Keeping your setup, this would be done during delivery into the
POP mailbox. Then when fetching the mail, pipe it through the
reverse operation.

What I describe is of course a kludge. There are other ways
to do this correctly, starting with good old uucp, ending with
setting up a VPN connection between your sites and letting the
MTAs speak directly to each other.

HTH, HAND.