Charles Gregory wrote: > Could I just clarify this discussion? It started out with a specific > comment about greylisting, which I am preparing to implement. So naturally > it concerns me as to whether these remarks about 'big name' non-compliant > MTA's still apply specifically to greylisting. I mean, I can't really > imagine a 'big' (fortune 500?) company having an MTA that does not attempt > to resend mail if it gets a 400 response from another MTA.
It depends. We changed our greylisting code to greylist after DATA rather than after each RCPT after observing the following behaviour from a big-name MTA: C:HELO S:220 smtp.example.net Go ahead C:MAIL FROM:<[EMAIL PROTECTED]> S:220 Sender OK C:RCPT TO:<[EMAIL PROTECTED]> S:451 Greylisted... try again later C:RCPT TO:<[EMAIL PROTECTED]> S:451 Greylisted... try again later C:DATA S:500 Need recipient first Oops! The MTA authors obviously hadn't checked their state machine carefully. Regards, David. _______________________________________________ Help us build a comprehensive ClamAV guide: visit http://wiki.clamav.net http://www.clamav.net/support/ml
