EIGRP query

[mukundh86]

Hi all,

I have the followiung setup for EIGRP routing:

Router A is connected to Router B through point to point GRE tunnel. Both A and B have tunnels to other routers, but EIGRP is running only between A and B. A has a directly connected 172.16.21.0/24 behind it and B has 172.16.71.0/24. When I configure the eigrp on both the routers,I see the other tunnel IPs for the other routers learnt through eigrp. for example, I had the following eigrpconfigs on A and B respectively

router eigrp 1000

network 172.16.21.0

no auto-summary

router eigrp 1000

network 172.16.71.0

no auto-summary

What's happening is that if B has a tunnel IP 172.16.30.1/30 to another router, I see 172.16.30.0/30 in A's routing table learnt via EIGRP. I was able to get around this by adding distribute lists on B to advertise only 172.16.71.0/24 out through the tunnel to A. But is there any reason why this happens? I thought B will advertise only 172.16.71.0 as only this is stated with network command.

Also, if I advertise 172.16.21.0 with the mask, I don't see this network learnt at A through EIGRP. That is B if I enter

router eigrp 1000

network 172.16.71.0

no auto-summary

I don't see A learning 172.16.71.0 through eigrp. Any thoughts?

Thanks

Mukundh

[Peter Paluch]

Hello Mukundh,

Your network commands are missing the netmask argument. If you verify the running-config, you will see the router has automatically changed the address to 172.16.0.0 and assigns all directly connected interfaces falling under this large network to the EIGRP. So the first thing to watch for is about being as specific as possible when writing the network commands.

However, to answer the rest of your question, I need to know the IP addresses that are used as tunnel sources/tunnel destinations. Do they also fall under the 172.16.0.0/16 scope?

Best regards,

Peter

[wilrow113]

If it was me I would set up the eigrp with the interface address

Router eigrp 1000

Network 172.16.29.0 0.0.0.255

Network (tunnel address) 0.0.0.0

No auto

Eigrp has to no the network used for the tunnel between the routers

Sent from Cisco Technical Support iPad App

[Vinayaka Raman]

Mohan,

Use show ip eigrp interface command on router B to check if eigrp is turned ON on 172.16.30.0/30  interface. It should be ON with the network command you had given. You can simply turn it OFF by using the right wild card mask, as you decided not running eigrp on this interface.

I don't see A learning 172.16.71.0 through eigrp. Any thoughts?

Can you check what is the route learned for 172.16.71.0 at A, using show ip route 172.16.0.0?

If you seeing a summarized route, use right wildcard mask. 

hope this helps.

[EPHRAIM MANI]

hi Mukundh,

Please let us know the current status, please read Peter Paluch and do the necessary cofiguration. Please update. Also poste sh ip eigrp int command output from both the the router (A and B) as advised.

Thanks