my postfix config includes
unknown_client_reject_code = 550
per docs, I understand
The SMTP server always replies with 450 when the mapping failed due to
a temporary error condition.
generally, does what I want.
a legit sender, sending from their provider, accidentally typo'd their own
sender address
legitsen...@example.con
instead of, correctly,
legitsen...@example.com
my postfix instance does what I intend, and 'rejects' ...
2020-10-28T13:15:23.753811-07:00 svr017 postfix/postscreen-internal/smtpd[24098]: NOQUEUE:
reject: RCPT from smtp.clearbearing.net[64.25.214.9]: 450 4.1.8 <legitsen...@example.con>: Sender
address rejected: Domain not found; from=<legitsen...@example.con> to=<m...@mydomain.com>
proto=ESMTP helo=<obermeyer.clearbearing.net>
but, I note, only with the temporary '450' -- not my intended '550'.
the issue i'm trying to solve is that the server on their end keeps resending
the reject-ed msg every 5 mins.
been going on for days.
the sender themselves can't cure it.
their provider, 'clearbearing' has been repeatedly notified @support, asking
for them to clear their queue of this message, and to fix their resend timings;
so far no response/action.
i'll deal with them separately.
i _do_ need to keep receiving mail from the legit sender, from this^ provider's
server; so can't simply block it outright.
questions:
(1) _is_ unknown_client_reject_code the relevant code here?
(2) if so, what are the specific conditions for a 450 override due to "a
temporary error condition"?
(3) what's the mechanism in postfix to force the 550, under this^
condition, for just this one send?
my inclination is to say the heck with it, let it spew endlessly, and let
postscreen do its job ...
but I am interested in the narrow-case exception handling.
