Can't open display:

[Simon Andrews]

 >> I there is a "-nolisten" option to the X server which tells it not to
 >> listen on port 6000.  I this is the problem in your case you should 
 >> see it in the process table (ps -ef).  When nolisten is on, only
 >> local processes can connect to the display.

Gates, Robert L . wrote:
> Bob,
> You are on to something. My ps -ef does show that nolisten was passed to
> the command stream. Now, the question is, where do I go to modify this
> behavior?

/etc/gdm/custom.conf

#DisallowTCP=true

Uncomment and change to false.  Restart gdm.

Please bear in mind that opening up remote X isn't a great idea from a 
security point of view.  Using X tunnelling though ssh is a much better 
idea. (Simply do ssh -X user at hostname from your remote machine).

Simon.