Marc
> Now, I am not yet sure WHY the messages are coming back to me - whether it is faked FROM by a spammer, or somebody careless joined a > mailing list using a fake email address, that happens to be in my domain - OR - my fear that I am actually OPEN as a relay and being used.
It's a dictionary spam attack against AOL, and your domain has been used for
thousands of different 'from' addresses - so has one of mine :-(
If your setup will allow it, you could ':blackhole:' a default localpart in
the domain concerned, which will make them go away - or alias the default to
a real mailbox which scoops up the NDRs and gets them off your queue.