We have been receiving over 20k of spam from .it domains almost daily! What can we do to drop emails from these domains beside marking them as junk which failed to even move most of them to the junk folder?
We also suspect that some of them are from our internal users who have infected computers. Unfortunately the Origin IP of every emails simply show up as 127.0.0.1. The Zimbra log also shows 127.0.0.1 for most email senders instead of their actual IPs.
I have posted this few week ago before but unable to receive any satisfactory reply. We have no choice but to repost as this is getting more serious without any solution or even workaround in sight. Anyone with experience with spam issue please share your expertise. Thanks!