I have finally admitted defeat, and I hope that someone here can give me
some much needed guidance. Let me explain the goal:
1) Have a mail gateway that runs a filter on all incoming mail. If the
filter rule = true (ie. It checks for those script worms. The regex was
kindly done by Nigel.), do two things:
a. Send an e-mail back to the sender letting them know that the attachment
was denied, and to send it again as a compressed file.
b. Send a mail to the recipient that the sender tried to send an
invalid-attachment message.
2) If the filter does not get tripped, then forward the message to an
internal mailserver.
Here's some thoughts/notes as I tried to come up with a solution:
- The system is OpenBSD 2.6 with all patches running Exim 3.14 compiled from
the tarball off of one of Exim's mirror sites.
- There are no local user accts on the machine. Ideally I would think that
keeping local_domains blank would be the 'proper' way to do it. I could be
wrong....
- The closest I got to success was by allowing relaying from all locations,
and using the 'domainlist' driver as noted in Q0302
(
http://www.exim.org/FAQ.html#SEC53) of the FAQ. The problem I had here was
I couldn't figure out how to set up the filter in this scenario. Also,
allowing relaying makes me uneasy, and if I had to allow relaying, that only
allowing relaying to designated hosts would be allowed (in this case our
internal mailserver).
- The system-wide filter doesn't seem a good choice because I want to be
able to do #1(b) above (I want to be able to do it on a per-address basis).
I am not sure what other useful information that I could provide. I've been
working on this for about 12 hours, so my brain is somewhat cooked.
Much thanks in advance,
Eric
ericb@???
