24.07.2012 10:49, Morten Stevens: > No, greylisting is really a bad solution. It is not RFC compliant and > delays the mail traffic.
No. Rejecting mail with an temporary error is perfectly RFC compliant. It happens all the time without greylisting. Because the authors of the SMTP RFC knew that there are many different possible reasons why a mail server might temporarily be unable to receive mail, they added the 4yz responses to it. With greylisting done right, only a very small part of (wanted) incoming mail is delayed. And for the rest: e-mail isn't guaranteed to be a real-time communication channel. -- Regards mks
