I agree whole heartedly, so I've set all the amavisd rules to D_REJECT, but I still get the "Undeliverable:Undelivered Mail Returned to Sender" bounces. How do I turn these off?
If you're post-queue, you can't use D_REJECT.. It's too late. You've got to use D_DISCARD or D_PASS.
Since the message has already been queued, D_REJECT and D_BOUNCE are going to result in the same thing. D_REJECT only works if you filter at delivery time. After all, if you've already accepted the message, you can't go back in time and reject it.