My sending host does, in fact, have proper FCrDNS. I've contacted AT&T in an attempt to get my IP address off their block list. They haven't replied yet, and since I contacted them only yesterday, it's too early to tell if they are going to do it or not.
Distinguishing "block list" rejections (which I would want to retry via my smarthost) from other sorts of rejections (such as "no such user") could, I agree, be an issue. In theory, I might want to try looking at the SMTP rejection notice and do a "retry via smarthost" for anything that did not contain one of a limited set of extended status codes (such as the 5.1.x codes). I'm not sure if Postfix has any way of being told to do this sort of thing or not. Rich Wales [email protected]
