> How would you find an unknown ip of an unknown machine? About the > only *chance* you have is doing MX lookup's and hoping that email > comes from that same server. If their organization uses various > relays and proxies to send, you are out of luck. There's no way to > get that information without a previously harvested email and looking > at the message headers. >
Well, that's exactly the point... you don't find the ip. You put in a temporal entry that says 'whitelist the next ip address that connects attempting to send mail from $sender to $rcpt'. After that, the entry expires. It's been pointed out here that it just isn't possible, currently. I'm ok with that. The issue is smaller than the problem that it solves (removing most of the spam from my networks). Thanks for all the input. --James
