On 2026-08-10 at 20:34:09 UTC-0400 (Mon, 10 Aug 2026 19:34:09 -0500)
Scott Techlist via mailop <[email protected]>
is rumored to have said:
That helps but even though I think I invented greylisting about 20
years ago, I don't do it any more. A five second greet pause to newly
seen sending IPs seems to catch about the same set of bots without
the annoying delays and lost mail.
John, maybe I should ask on the Postfix list but sicne you mentioned
it; this doesn't cause issues with "real" servers who don’t wait to
talk then? Will they retry and pass next time? I see postscreen has
the postscreen_greet_wait = 5s option, that I'm not using.
No such servers exist.
Greeting pause has been such a perfect and cheap tool for decades that
it is unimaginable that any sender could succeed while violating the
rule that they must wait for a complete banner before sending any
commands. Timing out in less than 30s during the wait for a full banner
(i.e. rather than just fast-talking) is also a very low-yield sending
tactic.
No one will care about sender complaints of timing out if they've set
their timeouts below the RFC5321 minimums.
--
Bill Cole
[email protected] or [email protected]
(AKA @[email protected] and many *@billmail.scconsult.com
addresses)
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