Debian 5 Network issue

[fieryhail]

Hello,
I've got a strange issue. Running Debian 5 and everything has been running well until recently. Had a power outage where UPS didn't keep up and now netorking has been corrupted on the Debian system. It's a virtual machine under VMware ESX 4.1, networking is setup properly on the ESX side as there are other hosts in the same network that have no issues. Physical connectivity is to a Cisco Catalyst 3550 Layer 3 switch which is also functioning properly.

Problem is as such:
eth0 is: 192.168.20.11
Subnet Mask: 255.255.255.0
Gateway: 192.168.20.1

I can ping the localhost itself, I can other ping other hosts in the same network such as 20.2, 20.3, 20.4 etc.
I can ping the Debian system from other hosts in the same network with no issues
I can NOT ping the gateway (192.168.20.1) from the debian system
I can NOT ping the debian system from the Cisco Catalyst (although all other hosts are fine)
I can NOT ping the debian system from any host OUTSIDE the 192.168.20.0 network (not surprising given the current state of affairs)
I can NOT ping any host outside the network FROM the debian system (also not surprising)

I checked the /etc/network/interfaces and all appears correct, the resolv.conf is also accurate. If I try to restart the network (/etc/init.d/networking restart) it only makes things worse, then I can not even ping other hosts IN the same network. Really quite strange. Any ideas on what happened/how to fix it?

Thanks in advance!

 

[fieryhail]

Just an update, I modified the /etc/network/interfaces file and /etc/hosts file to reflect new IP information, basically changed the internal network from 192.168.20.0 to 192.168.10.0. I also changed the network in ESX to the corresponding 192.168.10.0 network, and finally the NAT and ACLs in the PIX to reflect the new IP settings. Everything works fine again, but still have NO CLUE why there is an issue with the 192.168.20.0 IP settings. As stated in earlier post, all other hosts on that network function perfectly. Although things are back up and working again, I'd still love to know why this occurred, any thoughts are welcome. Thanks again.