Current behavior to set DSCP EF code point by default is harmful

[Colin Watson]

On Sat, Apr 11, 2026 at 11:58:07AM +0000, Job Snijders via openssh-unix-dev wrote:
>On Sat, Apr 11, 2026 at 10:51:51AM +0200, Hendrik Visage wrote:
>> Well... since Trixie/Excalibur (Debian 13 / Devuan 6) I've seen some
>> SSH network "hangs" which might just be explained by these bits and
>> the networks I cross.
>
>No, you have now in fact added a point to the contrary: these "hangs"
>you report are entirely unrelated to any of the changes under
>discussion, because Debian Trixie shipped with a debian-specific set of
>patches applied to version of 10.0.

I think Job knows this, but for completeness: I dropped the relevant 
patch post-trixie, given the changes in OpenSSH 10.1.  That patch is one 
that we had been carrying for quite some time, since Debian 10 (buster), 
so I share Job's scepticism that behavioural changes between recent 
Debian stable releases can be chalked up to this.  (That patch was an 
attempt to solve integration problems by reverting to the behaviour of 
OpenSSH < 7.8, but I'm willing to accept that it was a mistake at the 
time.)

I'm not necessarily opposed to backporting the relevant changes to 
trixie and dropping the relevant Debian patch, but I make no pretence at 
being a network engineer, so it really needs to be an uncontroversial 
change or at least one I can have help in persuading Debian's stable 
release team to accept.  I think the relevant commits are 
65909fa114e7dd7511800db2b7bacb8774afe887, 
ec3465f59c651405e395092f3ad606f8992328d8 (maybe), and 
289239046b2c4b0076c14394ae9703a879e78706, but I would be happy to take 
advice on that.

This thread doesn't make it 100% obvious that such changes would be 
uncontroversial.  I can't find any Debian bug reports indicating 
problems with QoS since we adopted the changes in OpenSSH 10.1, which is 
useful to know though not definitive (it took about eight months for 
reports about iptables and VMware problems with the changes in 7.8 to 
arise).

-- 
Colin Watson (he/him)                              [cjwatson at debian.org]