On 23 December 2016 at 17:36, Richard Shetron <gue...@sgeinc.com> wrote:
> Maybe they were using some type of grey listing. > > For those who don't know: > Grey listing is where the target MTA rejects with a retry error code the > email from a new source for some period of time. Every site can set their > own delay. Most spammers won't retry so it gets rid of a lot of spam. > Real email servers will accept the retry error (4xx) and retry after some > prefigured time from a few seconds to an hour or more. The IP addresses > are tracked and if retried after the time limit are white listed for > anywhere from a few hours to a month or more. > I know Exim will only treat a session as a failure if it gets 5xx. Does Postfix do the same? -- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254 7 3200 0004/+254 7 2274 3223 "Oh, the cruft." ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org https://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: https://mail.python.org/mailman/options/mailman-users/archive%40jab.org
