I have a Cisco 2611XM. I've configured FE 0/0 as the port to connect to my cable modem. FE 0/1 is my lan port, which connects to my Cisco 2950.
The cisco 2611XM is setup as a DHCP server, it gives out ip addresses fine, all computers on the lan can communicate and they get the correct default gateway (the ip of FE 0/1). They can ping the ip of FE 0/0 as well, but they can not ping the gateway beyond that, nor can they ping any other external ip (obviously).
When logged into the router I can ping all ip's just fine and I can resolve dns (I can ping google.com).
I'm obviously missing something simple, and I just can't figure it out. This is an older router I've had for some time and I have no service contract so I can't call TAC for help.
All ACLS are turned off for the sake of troubleshooting. If you need any additional information I can provide it, but I'm hoping I overlooked something simple.