Re: TCP connection ignore RST

From: Youssef GHORBAL <youssef.ghorbal_at_pasteur.fr>
Date: Tue, 07 Sep 2021 07:32:29 UTC

> On 7 Sep 2021, at 04:11, Rozhuk Ivan <rozhuk.im@gmail.com> wrote:
> 
> On Sat, 4 Sep 2021 13:19:52 +0200
> Michael Tuexen <michael.tuexen@lurchi.franken.de> wrote:
> 
>>>> On 4. Sep 2021, at 01:37, Rozhuk Ivan <rozhuk.im@gmail.com> wrote:
>>> 
>>> Hi!
>>> 
>>> 
>>> I have strange case: FreeBSD 12.2 ignore TCP RST from windows host
>>> and continue retransmitting packets. sockstat show that socket
>>> connected even after many tcp rst packets received.
>>> 
>>> Any ideas how to fix it?  
>> Where is the trace taken? On the Windows side or on the FreeBSD side
>> or somewhere else? Could you provide the .pcap file?
>> 
> 
> From FreeBSD side.
> 
> https://urldefense.com/v3/__https://reviews.freebsd.org/D28142__;!!JFdNOqOXpB6UZW0!-L413Hh53wGbdWDDnQnsq9zonlTlshjMS5-FW9WiH7ga68R8mqQ0AyNC6apUbMi-BORQwNV-$  e82353f84c58da9a5c38bd471a09936c16a5b6ea
> https://urldefense.com/v3/__https://reviews.freebsd.org/D28143__;!!JFdNOqOXpB6UZW0!-L413Hh53wGbdWDDnQnsq9zonlTlshjMS5-FW9WiH7ga68R8mqQ0AyNC6apUbMi-BHNJHDEF$  d05d908d6d3c85479c84c707f931148439ae826b
> sysctl net.inet.tcp.tolerate_missing_ts=1
> this fixes issue for me.

Humm, the first commit already fixed the case of RST packets missing TS, and you are reporting that RST get ignored. I don’t see how the sysctl (meant for non-RST segments) could have helped.

Youssef