Sorry, I haven't read all the responses so far, here's my list of suggestions/comments. By default for some years now, the TCP port has been disabled for X, instead it's suggested one use ssh tunneling. This is set in the /etc/X11/xdm/Xservers file, most likely has --nolisten tcp on the X line. The better solution is to just use ssh by calling ssh -Y machine, which sets up a tunnel which should give you a display variable. The only reason you should have to manually set a display variable is if you're using X over TCP instead of over ssh. In case you're wondering about ssh -X vs -Y, I don't know. I do know that -X seems to time out after a few minutes, so if you ssh -X machine, then 10 minutes later decide to run something, the tunnel no longer works. ssh -Y seems perminant. Perhaps that is why it's called "trusted". If you can ssh into the machine, you can run applications over it, no additional ports are used. So.. localmachine# ssh -Y remotemachine user/login remotemachine# firefox And it'll work, firefox will come up on localmachine. I can't imagine why it wouldn't.
