network failure after unsigned yum update in FC4t2

[Xiyang Chen <settinghead@xxxxxxxxx>]

Hi, 

I had a problem after "yum update" my FC4t2 system. It got stuck at
"determining IP configuration" for quite a long time when starting up,
and the system could boot successfully but the network failed to
function correctly. The DNS service seemed completely down.

Here is the error message shown on screen when booting:
icmp open socket: Permission denied.

What caused this? Any solutions?

Thanks.

Xiyang