Default gateway not configured after FC6 installation

[Timothy Alberts]

I installed FC6 on a system and found that the default gateway is not
listed in route.  I can add it manually to route with (route add default
gw gatewayip) where gatewayip is my router.  However when I reboot, it
dissappears and I have to manually enter it again.  How do I fix this so
I don't have to keep doing it after every reboot?