Tunnel X11 applications with SSH

This page explains how to start remote X applications (also called X clients) easily and securely. This is the recommended way to run all remote X applications and is the required method for running off-site X applications which need to be displayed at CERN.

Most desktop computers do or can run an X server. This is true for X terminals, UNIX workstations and Windows PCs with an X emulator such as X-Win32. When your desktop computer runs an X server you often need to start remote X applications, i.e. applications not running on your desktop but with the windows displayed on your screen.

Displaying X Applications on Windows PCs

You can display remote X applications on your Windows system by installing "X-Win32" following the instructions provided here.

Displaying X Applications on UNIX Systems

You can display remote X applications on your UNIX system using SSH as described below. SSH will encrypt your sessions and is the preferred method.

Encrypting X Applications using SSH

The recommended way to start a remote X client is to use ssh with its X11 forwarding feature enabled (this is the default at CERN). You can either start an interactive session with ssh and start an X client (by simply typing the command name) or directly start the remote command with:

$ ssh [-l <remote-user-name>] <remote-machine> <command> [<arguments>] 

For example:

$ ssh lxplus001 xload
$ ssh -l root myserver xterm -ls