Bug#1111446: openssh: IPQoS changes upstream and debian revert-ipqos-defaults.patch since 2019 (#923879 and 923880)

On Mon, Aug 18, 2025 at 08:30:40AM +0200, Ludovic Pouzenc wrote:
>I get there while doing tcpdump capture on ssh IPv6 traffic and seen
>"invalid" values in DSCP field (in respect to IANA defined values) with
>a default sshd config on Debian 13. It seems identical in unstable.
>
>I see a patch qualified as "temporary" in #923879 from 2019 that is
>still applied on Debian 13, named revert-ipqos-defaults.patch.
>
>Mentionning that to friends, one of them points me to recent changes
>commited in openssh around this topic, that, I think will make debian
>revert patch unappliable or introduce a change in behavior, pushing
>default system DSCP values (CS0 I beleive) instead of non DSCP compilant
>curent values.
>
>https://marc.info/?l=openbsd-cvs&m=175396095604983&w=2
>
>This patch is still applied, saying that there was a bug in iptables -m
>tos in 2019. I never found a clue that is was reported nor considered
>upstream. Debian bug #923880 still open and seems to be in a dead state.
>
>Could you reconsider revert-ipqos-defaults.patch for testing+unstable ?
>As mentionned in one the two BR, Fedora since 2019 choosen to not revert
>IPQoS default values and I am not aware that there is problems with that
>nowadays.

My plan is to drop that patch when there's a new upstream release and I 
integrate it.  That way, if it still causes regressions in other 
software, at least we only have to debug them once.