I installed Fedora Core 3 a couple of weeks ago, and X has been working
perfectly with my setup (no problems with gfx card, etc). Yesterday I
installed a simple home network that accesses the internet via ADSL.
Networking seems to work perfectly, but whenever I logout X crashes.

More specifically:

* X starts fine when I boot and login.
* I get a blank screen when I logout and the keyboard is locked out.
* This happens with both GNOME/gdm and KDE/kdm.
* It also happens when I restart X with ctr+alt+backspace.
* If I disable networking, the problem goes away.
* The problem is not intermittent and consistently happens every time I
start my machine and login and out again.
* I'm running X 6.8.1 with a 2.6.9-1.667 linux kernel.

Any ideas what's going on here?