Routing Loop

[projectit]

Hello:

I have two 2620 router connected by FT1. From the remote site I cannot ping an specific IP address. If I tracert from the command prompt all I get is a loop between the 2 routers. The config is a simple one running RIP and EIGRP protocols. Any Help.

[amit-singh]

Hi,

You must be having a duplicate route entry in your route table. Please describe the n/w topology more.

Show IP route and the configs from both the router would be handy.

regards,

-amit singh

[projectit]

Currently there's a 2620 router at the corporate office and 2620 at the remote location. The connection between the routers is a FT1. At the corporate office there is a gateway to the internet which is not the 2620 router. Now this is the only remote link going to corporate that connects to a 2620 router. I have 4 other remote links but they are all connected to a 2840 router which is working fine. attach the ip route printout. Thanks

[Richard Burts · Accepted solution]

The problem is relatively clear. On the remote you are learning a number of dynamic routes via EIGRP on serial 0/0 and you also have a static default route pointing at serial0/0, So anything the router is going to forward is being forwarded out serial0/0.

On the corporate router you are learning a number of dynamic routes via EIGRP ad RIP on FastEthernet0/0. And you have a static default route pointing to serial0/0.

It is the fact that the two default routes point at each other that causes the problem. If the remote forwards something to the corporate that is one of the subnets in the table it should work. But if the destination is not in the routing table then the corporate router forward to its default route which is back to the remote. So remote sends to corporate, corporate sends to remote, remote sends to corporate,... repeat till TTL expires.

I can understand why the default at the remote points to serial0/0. But I am very puzzled why the default at corporate points to serial0/0 which is back to the remote.

HTH

Rick

[projectit]

Rick:

Thanks for answering. I took the static route from the corporate and now i'm able to forward packets outside my nt. Thanks.