Methinks there is a candidate meta rule here. SPF passes and it's in certain of the BLs leads to a higher score than merely being in the BL.
In particular, an SPF (or similar) pass will make RHSBLs (right-hand-side blacklists, for those following along) more useful.
I mean, if someone forges a mail from [EMAIL PROTECTED], that's dumb. They get a point or two for stupidity. But if knownspammer.biz goes to the effort to set up an SPF policy and sticks to it, the combination SPF pass and RHSBL hit is pretty conclusive.
(Me, I'm just looking forward to the day that people stop bouncing mail sent using forged addresses. I checked the number of "User unknown" hits we handle per day, and it's more than 10 times the number of messages that make it through to an actual mailbox.)
-- Kelson Vibber SpeedGate Communications <www.speed.net>
