[plug] sshd help (take2) [UNCLASSIFIED]

[Clark Julian]

> -----Original Message-----
> From: plug-bounces at plug.org.au 
> [mailto:plug-bounces at plug.org.au] On Behalf Of Denis Brown
> Sent: Tuesday, 8 February 2005 12:24 PM
> To: plug at plug.org.au; plug at plug.org.au
> Subject: Re: [plug] sshd help (take2)
> 
> Thanks, Craig and Tim.
> 
> Tim: no chance yet to check the aspects you mentioned.
> Craig:...
> 
> At 11:33 AM 8/02/2005, Craig Ringer wrote:
> >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
> 
> <snip>
> 
> >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.
> 
> I thought as much!   In fact many times I have ssh'd into a 
> machine, using 
> the same user credentials either from additional instances of 
> PuTTY on one 
> machine, or from several individual machines.
> 
> >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.
> 
> Nod.
> 
> >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.
> 
> Thanks.  As above to Tim's suggestions, no physical machine 
> in front of me 
> now.   But what you say gels quite nicely.   Consider that 
> using the init.d 
> scripts to do the sshd start/stop/restart produces some interesting 
> effects.   Namely that if the sshd process is still "healthy" 
> then I can 
> start, stop, restart it to my heart's content.   If the 
> "master" sshd as 
> you put it becomes unhealthy though - and maybe forgets to 
> fork off child 
> processes, or kill them - then attempting a sshd stop results 
> in red !! 
> marks on the resulting output line (on the root console) and 
> subsequent 
> attempts to start or restart it brings forth the message that 
> the sshd is 
> already running.   Having a look at the sshd script (in 
> /etc/init.d) shows 
> that it is trying to identify the sshd (master) process 
> through its entry 
> in /var/run/sshd.pid, if that file in fact exists.
> 
> In the face or the error messages mentioned above, a ps -A 
> shows no such 
> sshd process running and /var/run does not contain an shd.pid file 
> either!   Somehow or other the process "engine" has gone off 
> the rails at 
> least as far as sshd is concerned.   The init.d script in 
> fact uses the 
> start-stop-daemon which, according to text strings within it 
> hails from 
> Debian so I'm a little loathe to blame it :-)
> 
> It was on the basis of the observed bizarre behavior with the 
> "already 
> running" but invisible sshd that I unemerged and re-emerged 
> sshd last thing 
> last night.  But to no avail.   I'll throw this one at the 
> Gentoo forum for 
> comment.   Perhaps I should add that this is a fresh 
> installation and I am 
> reasonably sure that I have a valid kernel - no silly 
> mistakes in config 
> and that otherwise everything else on the system seems fine.
> 
> At this point I do not know if I am facing two probems or 
> just one... if 
> one then the misbehaving master sshd would be the problem.   
> If two then 
> I'd pitch for some PAM-related mischief or misconfiguration.  
>  Driving home 
> it occurred to me the significance of the [net] and [pam] 
> sub-processes...    When an incoming conection attempt is 
> made there would 
> logically be a [priv] part, then a [net] part while network-related 
> activities took place.   This would be succeeded by a [pam] part for 
> authentication.   Once authentication was achieved that process (sub 
> process?) could die off, then the [net] sub process, leaving only the 
> [priv] and userland parts intact until either logout or connection 
> dropout.   Corrections to the above most gratefully recvd!
> 
> Thanks,
> Denis
> 
> 
> 
> _______________________________________________
> PLUG discussion list: plug at plug.org.au
> http://www.plug.org.au/mailman/listinfo/plug
> Committee e-mail: committee at plug.linux.org.au
> 
> 

Hi Denis,

I've been using sshd under gentoo without any difficulties.
It seems strange to me, because mine worked pretty much straight out of
the box.

Maybe there's a problem with your sshd configuration file 
Perhaps you could post the contents of /etc/conf.d/sshd

I'll copy my sshd conf file and send it through tomorrow if you'd like?

I can't send it now, cause I'm at work. :-(


Cheers,

Julian Clark


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