Operations > Computing > FAQ

Unix VNC Sessions

VNC allows graphical programs (e.g. MATLAB, CAD software, etc.) to be run remotely with the ability to reconnect to that session should the network connection fail. The EE Linux Lab systems have VNC software installed. Recommended clients include Chicken on Mac OS X or the TightVNC Java Viewer on Windows.

VNC sessions will not be able to be setup if your EE account is over quota.

Start a VNC Session

  1. Connect to an EE Linux Lab system using a SSH client. It is best to use linux12 through linux26 or linuxsrv01.ee.washington.edu.
  2. Run vncserver -list to see what sessions have been started.
  3. If none have been started, launch a new server with the following command:
    vncserver -interface

    The first time, a password will be asked for; this password will prevent other users on the same system from accessing your session. If you forget this password, see below on killing and setting things up from scratch again.

  4. Now the -list command should show a session (the numbers will vary):
    linux13$ vncserver -list
    TigerVNC server sessions:
    :1		5528
  5. Use the lsof command to show the port number the process is listening on, in this case 5901. The port number may vary if other sessions exist. This port must match the port used when connecting with the VNC client.
  6. linux13$ /usr/sbin/lsof -i -P | grep vnc | grep localhost
    Xvnc 7131 nemo   6u IPv4 594464   0t0  TCP localhost:5901

Connect to VNC Session

The VNC client will need to connect to at the correct port, in this case 5901. The SSH host should be the server that the VNC server was started on. On Windows, we recommend using the TightVNC Java Viewer.

Please note that if on your Mac OS X client your local username differs from your EE account name, you will need to specify your EE account name, for example by stating eeusername@linuxXX.ee.washington.edu instead of just the hostname. By default, Chicken.app on Mac OS X will use your local account name, which may be different from your EE account name.

Cleanup VNC Sessions

Use the vncserver -list command and then vncserver -kill command to quit any sessions that need not remain open.

linux13$ vncserver -list

TigerVNC server sessions:

:1		7131
linux13$ vncserver -kill :1
Killing Xvnc process ID 7131

Reset Button

Kill off any VNC sessions as in the previous section, then delete the ~/.vnc directory. This will wipe out any saved password for the VNC session:

linux13$ cd
linux13$ pwd
linux13$ rm -rf .vnc
# and to be really sure nothing is running...
linux13$ pkill -u $USER Xvnc

Then, head back up to the top of the page to start a new server listening. (Note: things will be more complicated if you have started VNC server sessions on multiple hosts. The easy way to avoid this problem is to not do that.)


Another option is to use Xming to run X11 applications, though this relies on an active connection, and will fail when the network fails for any reason. The Eight Fallacies of Distributed Computing might make for good reading.

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