Network problems

[Thomas E. Dukes]

Hello,

This is strange!  I don't even know where to start.  Everything was working
fine until yesterday about 1:00PM.

I am running a FC2 system.  I have a dynamic ip using ddclient to update.  I
run ifconfig and I have an ip address.  I can ping it with no problem.  I
can ping other internal hosts.  My ip is current with my dynamic dns
provider.

I have changed out network cards and even bought a new switch.  Still no
internet connectivity.  DSL modem works fine as it is currently connected to
this PC. So its not an ISP or modem problem.

I have not updated any packages since 04-01-05.  I have been out of town ten
days and was able to access my server remotely, even yesterday morning. I
have made no changes to any files.  Internet connectivity just stopped.

Any ideas where to begin?  I have been looking over logs and don't see
anything wrong.

TIA