>
> 5xx means: permanent failure. Period.
Then exim should return message to sender immeadetly but it does not.
Instead exim remembers that that remote mx is "failing for long time" and
does not even try to deliver new mails! If exim for some reason does retry
then it logs "Remote host closed connection in response to EHLO" and won't
retry it again for any emails for that domain! Only after 72 your it
returns email to sender.
pt., 27 sie 2021 o 14:37 Heiko Schlittermann via Exim-users <
exim-users@???> napisał(a):
>
> Hi,
>
> krzf83--- via Exim-users <exim-users@???> (Fr 27 Aug 2021 13:10:01
CEST):
> > Large email provider in my country uses 521 response at their MX for
> > some kind of delaying. They don't care that its against rfc1846
> >
> > rfc1846 says:" A host which sends a 521 greeting message MUST NOT be
> > listed as an MX record for any domain"
> >
> > # nc mx.poczta.onet.pl 25
> > 220-mx.poczta.onet.pl ESMTP
> > 521 5.7.1 Service unavailable; client [144.76.50.172] blocked using
> > postscreenbl.opbl.onet.pl.local
>
> From m PoV, they clearly state that they do not want connections from
> your IP. Not now, and not later.
>
> > Exim can't handle this and does not even log anything in that
> > situation. Exim does not retry delivery and after 72 hours fails and
> > returns message with
>
> I believe, Exim logs that.
>
> > all hosts for 'onet.pl' have been failing for a long time (and
> > retry time not reached)
> >
> > How can I make exim to log those delivery attempts that end with 521
> > response? How can I make exim retry deliveries that ended with 521
> > response?
>
> 5xx means: permanent failure. Period. If their intention is something
> else, it is up to them.
>
> Maybe some of them is reading on the mailops list. Try contacting them
> there.
>
> Best regards from Dresden/Germany
> Viele Grüße aus Dresden
> Heiko Schlittermann
> --
> SCHLITTERMANN.de ---------------------------- internet & unix support -
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