Back when we were using exim 3, we had a stanza in the system filter
which tested for missing message-id situations, and incremented the
spam rating for possible rejection.
Now that we're using exim 4 and spamassassin, I can see that SA has
three different recipes for detecting that message-id was added by a
relay (the test doesn't always work, although that's not the
particular point that I wanted to raise here); but we see quite a
number of situations where the logged message-id has evidently been
added by our exim on receipt, i.e presumably the received message
didn't have one. This situation doesn't seem to get spam-rated at
all.
There was some discussion in the mail archive about a year back on
wish items for exim 4, see the thread which includes
http://www.exim.org/mailman/htdig/exim-users/Week-of-Mon-20010820/029093.html
Are there any offers of a tested recipe for this, please?