is the following a general problem, or just one i am seeing?
Verizon does SMTP callbacks, connecting back to the MX of the envelope sender and trying to verify that the user exists
2003-12-01 10:09:05 1APbBa-000Ork-DY == foo.user@verizon.net <foo@psg.com> R=lookuphost T=remote_smtp defer (0): SMTP error from remote mailer after MAIL FROM:<nikkiadamczyk@gerbangmail.com> SIZE=5365: host relay.verizon.net [206.46.170.12]: 450 Requested mail action not taken-Try later:sc004pub.verizon.net
So this would connect to the MX of gerbangmail.com and try to verify that whatever@gerbangmail.com exists.
gerbangmail.com. 5h55m6s IN MX 0 sitemail.everyone.net.
If the MX (sitemail.everyone.net) doesn't respond fast enough for verizon, their tester times out, and the message gets 4xx'd.
interesting but utterly irrelevant. the question was not how verison decided it was spam. the point was that their server returned a 450 as opposed to a 5xx (550 looks good), and this causes net damage. randy