Bug#1080350: openssh-server: refuses further connections after having handled PerSourceMaxStartups connections

On Mon, Jun 09, 2025 at 12:35:17PM -0400, LeJacq, Jean Pierre wrote:
> I confirmed that this bug continues to exist in version 1:10.0p1-5,
> currently in testing.

I'm wondering if there's something generally broken with MaxStartups
in trixie, beyond this; I upgraded from bookworm, and since then I've had
generally very spotty MaxStartups behavior. I never needed to change
MaxStartups before, but now, my backup and Nagios runs keep failing
all the time, with things like:

  Jul 23 04:36:07 pannekake.samfundet.no sshd[10555]: drop connection #1 from
  [2a02:20c8:2640::b2ff:97a7]:39984 on [2001:67c:29f4::50]:22 Maxstartups

or

  Jul 23 06:16:07 pannekake.samfundet.no sshd[10555]: drop connection #0 from
  [2a02:20c8:2640::b2ff:97a7]:54792 on [2001:67c:29f4::50]:22 Maxstartups

Notably, this happened before I set MaxStartupsPerSource, and it happens
even if I set it to a value such as 3 or 10. But interestingly, I never get
a line like “Beginning MaxStartups throttling”. The last instance I got
of that was before my trixie upgrade (and now it's with non-capital s
for whatever reason).

I have also tried increasing MaxStartups 10:30:100 to 30:30:100.
This is not the new penalty behavior, as I've turned that off for the
Nagios host and it still fires.

/* Steinar */