SSH Tunneling X Windows on Linux

To find out which version of SSH you are running, type ssh -V at a command prompt.

OpenSSH 3.7 and Below

Type ssh -X cs.toronto.edu -l your_username. The -X flag is for tunneling X.

Run an X application like xeyes to test if it works.

OpenSSH 3.8 and Above

If you are using OpenSSH 3.8 or higher and having difficulties, try the following:

The -X flag has changed in OpenSSH 3.8 and later. By default now X11 forwarding applications run as untrusted clients. This may cause error messages with some applications.

To use X11 applications as trusted clients, use the ssh -Y flag instead of ssh -X.