Remote Graphical Desktop With GDM and KDM
Graphical Remote Control
Enable=trueIf there's no Enable line, add it. Save the file, and restart the display manager so the change will take effect. You can also use the gdmsetup utility to configure gdm graphically, if you prefer.
On the client side, just type
Xnest -query remotemachine.com -geometry 1280x1024 :1
If you get a security error, try xhost remotemachine.com on your local machine (this adds the machine to the allowed list) and then the Xhost line again. If you get a "Server is already active for display" error, check that you remembered to put :1 on the end: Otherwise the server will default to :0, which conflicts with your existing desktop. You can also try :2 if there's a conflict with:1.
For a more complicated setup, something like VNC may be better, but this method is quick, easy, and does a good basic job.
Article courtesy of ServerWatch