Here’s a quick way to show all available video modes available with your current combination of video driver and physical displays. If you’re hand tweaking /etc/X11/xorg.conf to your liking, you should avoid listing display dimensions that your system doesn’t support. This little tool will let you know exactly what’s available.

If you need to forward X the old school unencrypted way, you need to add one line to gdm’s custom.conf file and restart the desktop. Without this, the old “xhost +” won’t do a thing because the out of the box Xorg configuration includes the nolisten tcp flag.

I have a build machine that runs a build script every day, but it runs on a headless server. That’s not really a problem except that I get a lot of GTK warnings because there’s no display. To get around having these useless warnings in my build log, I start a vnc server so i’ll have a display available on this machine.

By default most linux distributions give you a single display assuming that you have a computer or laptop with just one physical display device. But there’s no reason you can’t take advantage of multiple sessions using your virtual terminals instead of just 1 gui with a bunch of text consoles.