Antispam false positives skyrocketing
I'm using 7.1.1 (licensed) and I'm seeing a huge increase in false positives in the junk folders.
1. Users of the zimbra server sending to other users in the same domain on the same zimbra server are finding themselves getting marked as spam. For example, firstname.lastname@example.org sent to email@example.com and triggers: BAYES_50=0.8, HELO_NO_DOMAIN=0.001, RCVD_IN_PBL=3.335,
RDNS_NONE=0.793, TO_NO_BRKTS_DIRECT=3.483, TO_NO_BRKTS_NOTLIST=0.001
-- This doesn't make much sense to me.
2. I've whitelisted, filtered, and check over some external users sending into users on the Zimbra server but they still end up in the junk folders.
3. It appears as though the spam assassin is blocking on the sender's home/office/mobile IP instead of via their SMTP server's IP. For example, a user on verizon is getting blocked due to verizon being blacklisted, however they're sending out through a valid SMTP. This is triggering RCVD_IN_PBL=3.335 however if I look up the SMTP server it's not blacklisted!
-- This appears to be the case on a lot of mail servers lately. My understanding is blocking from the sender's home/office/mobile IP is incredibly unreliable and a terrible choice for filtering against.
4. For myself, I'm finding it nearly impossible to keep legit mail from sites like godaddy out of my junk folders, while some non-english clearly spam never seems to trigger any spam filters.
Is anyone else seeing this type of behaviour?