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EIGRP Stub feature

In my lab, I have a core 7500 distribution router running IOS 12.2(8)T and a remote 3640 spoke site running IOS 12.1(5)T12. They are running EIGRP between them. I configured the remote 3640 with the EIGRP stub feature. When I fail the LAN port of the 7500 router, it does not send any QUERIES to the remote 3640 (good), but it also does not send any UPDATE packets to the remote 3640. Thus, the remote 3640 continues to keep in its routing table any subnets that the 7500 learned over its LAN port!! When I don't configure the remote 3640 as a stub, it removes the routes from its routing table (i.e., normal routing behavior).

Question: Is this normal behavior for EIGRP stub feature or is this a bug? I could not find any bugs on the Cisco bug search tool.

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Re: EIGRP Stub feature

If you have the 3640's routing table filled with routes learned by 7500' lan port and want that routing changes on 7500 be reflected on 3640, why are you configuring eigrp stub networking?! Just to filter 3640 routes? You can do that with distribute-lists... I suggest you to inject an default-route to the stub router and take a look to stub's routing table...

Answering your question... When 7500 sees lan failing, it send queries to all neighbors and mark the entry as "query pending" (ACTIVE). When it receives the replies to all the queries, the 7500 mark the entry as passive and you can say that the route converged (In your case, it doesn't send queries at all). Only when the route is passive, 7500 will send an UPDATE packet.

Try to see in the eigrp topology table how 7500 has the routes learned from lan port... (active?)


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