4.15. Troubleshoot routing issues
The best troubleshooting tools are show and debug commands, specifically show ip protocols and various routing protocol debugging commands. Let's take a look.
First, the show ip protocols command will show you the routing protocols configured on your router. Hopefully you have only one. Here is an example:
Router#sh ip protocols Routing Protocol is "rip" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Sending updates every 30 seconds, next due in 27 seconds Invalid after 180 seconds, hold down 180, flushed after 240 Redistributing: rip Default version control: send version 2, receive version 2 Interface Send Recv Triggered RIP Key-chain FastEthernet0/1 ...