Evgeniy Berdnikov via Exim-users wrote:
> On Tue, Dec 29, 2020 at 10:20:51AM +0700, Victor Sudakov via Exim-users wrote:
> > The packet dump is available at http://admin.sibptus.ru/~vas/2.pcap
> > You can see from it that exim's host opens a TCP connection to the
> > clamav host, the clamav host replies with SYN+ACK, but the exim host sends a TCP RST
> > immediately. Why could that happen?
>
> Normally tcp connection initiator should respond with ACK to SYN+ACK.
Have you looked at the actual packet dump? I mean, don't trust my word.
> It looks like firewalling issue,
This dump
http://admin.sibptus.ru/~vas/3.pcap was collected on the very
host where exim lives (95.170...). I can't imagine how any firewall could
be involved.
> I can't imagine how to produce such
> behaviour with socket API.
Neither do I. Moreover, the problem began after upgrading the OS from
FreeBSD 11 to 12.2-RELEASE-p1, and exim to exim-4.94_4. Maybe the OS is
to blame.
--
Victor Sudakov, VAS4-RIPE, VAS47-RIPN
2:5005/49@fidonet
http://vas.tomsk.ru/
