I figured it out finally.
The issue was that the actual contents of the
Reply_To field presented to the .filter are "name <address>",
but I was assuming that it was just "address", so the match regexp
was wrong. The command line test I used had just "address", so it
worked, even though it didn't work when actually applied. Here
is a simple .forward that implements this:
# Exim filter
if error_message then seen finish endif
#
# The reply looks like "name <address>"
#
if $reply_address matches .*campus\.edu>\$
then
unseen deliver somebody_else@???
unseen finish
else
seen finish
endif
If the email is from campus.edu it is forwarded to somebody_else. The
"unseen" in front of deliver and finish tell the filter that no
significant event was seen (even though one was), so at the end it
delivers the message to the To: recipient also. If the email is not
from campus.edu it goes straight to "seen finish", which is, as
described in the filter documentation, a black hole. Nothing is
delivered, and nothing is sent back to the sender.
Of course if the Reply_to header is faked the mail will still go through.
Regards,
David Mathog
mathog@???
Manager, Sequence Analysis Facility, Biology Division, Caltech
