Why when I try to vnc or ssh into suse linux sometimes the server hangs ... need to hard set server to login

Posted on 2008-06-18
Last Modified: 2013-12-05
I found this searching google and then purchased a "trial" membership for this site, because we are experiencing the same issue.  After my purchase and subsequent login to have the answer revealed, there was no answer to this question.
If anyone has any suggestions or areas to check, any info would be appreciated.


Recently, I can not ssh to my remote servers or vnc to the boxes.

When I do a ssh  command it will hang and can not get a the connection to a remote server.
I then try to vnc to the remote server my gnome desktop does not give me a login screen
it just display a gray screen and a cross mouse cursor.
If I reboot the remote server everything will work normally for a few days and same problem

I am a newbie to Suse linux and have to administor over 60 remote servers and some servers work
fine and some has the above mention problems.  I don't know where to start troubleshooting. And don't
want to reboot the servers all the time.  If you need any futher info just let me know.
Any assistance will be appreciated.
Novell, Suse Linux Enterprise server, sles10 sp1, behind firewall
Question by:abfab
LVL 76

Expert Comment

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There is not enough information to determine what your issue is.
One thing, why are you running the remote server in graphical mode?  You will likely fair better changing the runlevel in inittab to 3 multi-user.

What does the server do?  It might be running out of memory which will explain why everything works after reboot, but becomes unresponsive after several days.
When you do get into the system, have you looked at the logs for ssh, messages, syslog, etc. to see whether any errors were recorded?
Have you tried getting to a different server on the same segment and then accessing this server?  Just checking whether the firewall locks out this server for some reason.
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The gray screen with the cursor sounds like you logged in but you are using the twn manager.

You will need to edit the xstartup script located in the .vnc directory

Replace the following in the xstartup script

twm &


gnome-session &

Let me know if that works.

Author Comment

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When I checked the server there is no .vnc directory.. (that I could find - I am also new to linux).  The server freezes even if we try to just ssh via putty or while trying to use a vnc client.  Again this happens over time...  After a hard reboot of the server we are able to login remotely, but only for a time.

We are running SLES 10 sp1 kernel 2..16.54-0.2.5-bigsmp  

As with the last person, I am not sure where to start troubleshooting this problem  I am configuring the servers to runlevel 3 (no desktop) and see if tha helps.  But would prefer the desktop because I am not familiar with all of the conf files that yast and the interface takes care of when I make configuration changes.  (Learning curve... uuugh)

There was a suggestion to remove the /tmp/X0-lock and the /tmp/.X11-unix/X0 files and restart the services and see if that clears up the problem.    Once we find the solution we will post for all.. if we find the solution....

Thanks again
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Expert Comment

Comment Utility
It sounds like you have two problems: one with SSH, the other with VNCSERVER.  

With the first problem, when you cannot connect to a remote server, you can run "ssh -v" which will tell you what is going on between client and server.  You can use multiple "-v"s to get more detailed information.  

The second problem is VNC server configuration, as mentioned by xDamox.  I don't know how SLES starts the server.  Fedora has a configuration script in /etc/sysconfig/vncservers which tells the server how to start. This will say which user should get a vnc session.  Look in /etc/init.d for vncserver or similar to see how it starts.  

Finally, if the server works for a while, then stops working, it's probably not a configuration problem.  Take a look in /var/log/messages (or other files in /var/log) and see if something happened which would cause a failure.  

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Thanks very much.. I will look at those leads....

Accepted Solution

Alundrez earned 500 total points
Comment Utility
The problem is not SSH or VNC, you're looking at secondary issues. You're unable to SSH or VNC into the boxes as a result of the servers crashing in a way that doesn't bring them completely down.

I've seen memory leaks, constant memory swapping, etc happened on a server but it still ran some applications properly while intermittently killing other applications such as SSH and GNOME/KDE.

You should physically inspect your box through the console when you're experiencing the problem.

Run top then ps -ef and see what your server is doing.
tail -f /var/log/messages
check application logs
dmesg | less

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