HPC FAQ - X Windows
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Frequently Asked Questions
It is important for security reasons to use an encrypted X session, so that others cannot see your private information, especially your password. You will tunnel or tunnel your X connection through ssh. This depends on the proper client settings
On Linux, your client may be configured globally by default to set up forwarded X connections, or you may override the default with the -X command-line flag, or you may specify the tunnel on a per-host basis in your own configuration file. See the man ssh page on your Linux workstation.
On MS-Windows clients there is often a check-box in the session setup for X forwarding. This may be on a global basis or a per-host basis.
For more info about forwarding X11 connections with ssh clients, such as puTTY, see http://www.tldp.org/HOWTO/XDMCP-HOWTO/ssh.html. Note: this is an off-site link and could disappear without notice.
Check the DISPLAY variable to see if your X connection is being tunneled through ssh. If DISPLAY is set to a cluster node's IP number instead of your local workstation's IP number, then the connection is being tunneled. Use the command echo DISPLAY while connected to the cluster with X.