greylisting and particular MTA mail scheduling

Aleksander Dzierzanowski
Thu Jan 15 16:20:23 UTC 2004

On Thu, Jan 15, 2004 at 08:57:13AM -0700, Vernon Schryver wrote:
> I don't know enough to say much about much of that except the 270
> seconds.  I chose 270 seconds or 4.5 minutes as the default embargo
> after observing from my logs that many MTAs ignore RFC 2821 and
> retransmit after 5 minutes.  I also noticed that while some hit-and-run
> spammers retransmitted, few retransmit as long as 4 minutes after their
> initial attempt.

thank you, I checked few most popular MTA with default configuration
and with default greylist embargo. Here are results how fast mail
was finally delivered:

qmail - 6m 58s
zmailer - 7m 29s
exim - 15m 11s
postfix - 32m 35s
sendmail - 60m 27s
note that it was on not-used machine without any mail queue and without load.
Maybe this values can be useful for some of you.

Best regards
Aleksander Dzierzanowski
  Wirtualna Polska SA

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