LAN Traffic Disrupted When WAN Shutdown

[Chris.Shaw]

I have a Cisco 2801 ISR with IOS 12.4. It has a basic configuration with F0/0 connected to the public internet and F0/1 connected to my private LAN. My problem is when I administratively shutdown of F0/0, for testing purposes, my connectivity to the LAN interface, is lost. Interestingly however, when I connect to the router via console cable; F0/1 shows as being up and line protocol up and it can be pinged locally however from the router I cannot ping into the rest of the LAN. Executing the clear interface F0/1 command fixes the problem however I don't believe this behaviour is normal. When F0/0 is brought back online, all connectivity is restored. Please let me know if you require any further details or configuration commands, any help would be greatly appreciated.

Thanks in advance,

Chris

[Glenn Quesenberry]

Chris,

     This discussion forum is focused on the Cisco Small Business router series.  Your question/issue around the 28XX ISR series would be better served on the Netpro forum under "LAN Routing & Switching" located here.

Best Regards,

[Chris.Shaw]

Thank you Glenn

[Chris.Shaw]

Hi all,

just nudging this one. Any ideas would be greatly appreciated.

Thanks in advance.

[Nagaraja Thanthry]

Hello,

Can you please post the running configuration and the output of "show arp"

from the router?

Regards,

NT

[Chris.Shaw]

Attached is the running config as well as the capture of a test that I did from the console port.

Let me know if you have any questions.

Cheers