Missing default route on fresh FC5 install

[Jonathan Underwood]

Hi,

I just freshly installed FC5 on a machine previously happily networked
with a static IP with FC4. (The machine has only one network
interface).

However, using exactly the same settings for the network settings
(same static ip, hostname, gatweay, netmask and DNS servers) I am
unable to reach the network. When i look at the routing table, where
there was once three lines under FC4, there is now 2 lines, and the
missing one is the "default" route line.

Also, on bringing the interface up at the command line (ifup eth0) I
see this message:
RTNETLINK answers: Invalid argument

I am unsure how to fix this, or where the bug that I need to report lies.

Any advice?

Jonathan