Not shure how to do it in FC4 as i have currently Ubuntu installed.
Please post the output of:
If the default route does not point to your gateway, you can set the routing on the commandline with:
/sbin/route add -net 0.0.0.0 gw 126.96.36.199 eth0
where you have to replace 188.8.131.52 with the IP address of your gateway.