[plug] sshd help (take2)

[Craig Ringer]

On Mon, 2005-02-07 at 21:29 +0800, Denis Brown wrote:
> Sigh,
> 
> Not quite as simple as I thought!   Okay, the situation appears to be that 
> sshd sessions "hang about" in the process list so that even though the 
> vanilla user logs off, if that logoff was un-clean for some reason(?) then 
> the sshd process refuses to allow further connections.   For any 
> user.

That shouldn't happen. You can have many connections from the same user,
and when the ssh client is disconnected due to network failure the sshd
tends to hang around for a *long* time without impairing logins from
others.

It sounds to me more like the "master" sshd whose job it is to spawn an
sshd for each new connection might be having problems.

> This IS starting to turn into a show stopper especially as I had hopes of 
> remotely admin'ing the machine from home - while otherwise on 
> holidays!   If I go to the console and as root kill the sshd processes that 
> refer to the supposedly logged-out vanilla user then I can log in via ssh 
> as either non-root user quite happily.

> Thoughts appreciated.   Google is not too helpful on this one it 
> seems.   The PuTTY website FAQ does mention the error messages but puts 
> them down to Windows networking issues.   Okay I am not surprised but why 
> now, when in an earlier life it was all working fine?   In any event this 
> is looking more and more like a dyspepsia in Gentoo.

[asbestos on]
To be quite frank, I wouldn't be surprised. I work with a couple of
folks with Gentoo, and all have observed occasional random and bizarre
breakage, sometimes only fixed by recompiling the entire system (!!).
While the key word here is occasional - I'm really impressed by that -
I'm still dubious, and inclined to think this is probably Gentoo-
specific breakage.
[asbestos off]

> In case anyone was 
> wondering, attempting login from another Linux machine (Debian as it 
> happens) showed nothing helpful even with -v -v and -v as arguments.

Try doing a console login on your serve and stopping the sshd, then
ensure no sshd processes are still running (kill any that are). Then, as
root, run:

sshd -d

and connect to the server. It should log (and IIRC output) a lot of
information. Examining that may give you some clues.

-- 
Craig Ringer