Solved: eigrp stub killing remote router connectivity?

russelljones · ‎07-20-2007

Is the "eigrp stub connected summary" command keeping my remote routers from seeing each other? I know this is default configuration because I didn't add it. I know that I can add static and redistributed routes to this command. The attached routing tables show the summary is being propagated but that doesn't seem to be good enough to establish connectivity between the two remotely connected routers.

Richard Burts · ‎07-23-2007

Russell

Thank you for updating this thread to indicate the solution to your problem. Now it makes better sense. If the base image of the switch only supports stub routing in EIGRP that is a major problem when the switch is in the core of the network. With stub you form neighbor relationships but the stub is intended to be the remote router and a stub router does not advertise to neighbors routes that it has dynamically learned from other neighbors.

And it explains why there was no stub statement in the partial configs that you posted from the remote routers. And in my attempt to list the causes of the core not advertising one remote subnet to other remotes it did not occur to me to consider the possibility that the core was configured as a stub.

I am glad that you got it worked out.

HTH

Rick

HTH

Rick

View solution in original post

Amit Singh · ‎07-20-2007

Could you please attach a network topology and explain your problem again in brief with the listed routers in the topology. It would really help us in understading your problem.

After checking the routing table for the remote routers, it seems that they are getting the router fine and as expected. A brief topology will help us understanding the problem better.

-amit singh

purohit_810 · ‎07-20-2007

EIGRP is Cisco Propritory protocol, if you have any subnet on NON-Cisco device it will not propogate unless and until redistribution.

So, make sure you have all cisco device once.

Routing table has quit enough subnets, now i don't know how much subnet are in your Topology.

Second, some routes are automatically EIGRP does summarize and keeps routing table as smaller as required.

If you are never used any subnet that will not present at routing table, once you will use it... it will pop-up into routing table.

Regards,

Dharmesh Purohit

Richard Burts · ‎07-20-2007

Russell

I agree with Amit that it would help us if you provided some additional information about the operating environment.

I do note from the file that you attached that the core switch has learned the LAN subnet from each remote but that each remote has not learned the subnet from the other remote. One thing that could produce this kind of symptom is some aspect of split horizon at the core switch. But since we do not know anything about the configuration of the core switch we can not know if split horizon is an issue.

Another thing that could produce these symptoms is some kind of distribute list. But we do not know if any distribute lists are configured.

I note a few things in what you posted that do not make much sense. On router2 there is a map class for frame relay but the configuration of the serial interface does not show any frame relay. Also your description in the post talks about eigrp stub but the configuration of router2 does not have any stub.

Perhaps if you can clarify these issues and provide some more detail we might be able to find answers for your.

HTH

rick

HTH

Rick

russelljones · ‎07-23-2007

As it turns out the eigrp stub command was enabled on the core switch because it had the base IOS image installed. Only eigrp stub routing is allowed with this image. We upgraded the switch to the ip services image and I was able to disable stub routing, which allowed the switch to forward all of the routes it learned through eigrp. That solved the problem.

Thanks for all replies.

Richard Burts · ‎07-23-2007

Russell

Thank you for updating this thread to indicate the solution to your problem. Now it makes better sense. If the base image of the switch only supports stub routing in EIGRP that is a major problem when the switch is in the core of the network. With stub you form neighbor relationships but the stub is intended to be the remote router and a stub router does not advertise to neighbors routes that it has dynamically learned from other neighbors.

And it explains why there was no stub statement in the partial configs that you posted from the remote routers. And in my attempt to list the causes of the core not advertising one remote subnet to other remotes it did not occur to me to consider the possibility that the core was configured as a stub.

I am glad that you got it worked out.

HTH

Rick

HTH

Rick