Your colleague asks for your help with a strange EIGRP problem. He redistributed a network into EIGRP but for some reason it doesn’t show up in the routing table of one of the routers. You verify the redistribution commands are looking good and there are filters in action. Let’s see if you can find the root of this problem…


  • All IP addresses have been preconfigured for you.
  • Configure EIGRP on all FastEthernet interfaces.
  • Redistribute the loopback interface on router Spy into EIGRP.
  • Ensure router CopyCat does not see network /24 in it’s routing table without applying any filtering techniques.

It took me 1000s of hours reading books and doing labs, making mistakes over and over again until I mastered all the routing protocols for CCNP.

Would you like to be a master of routing too? In a short time without having to read 900 page books or google the answers to your questions and browsing through forums?

I collected all my knowledge and created a single ebook for you that has everything you need to know to become a master of routing.

You will learn all the secrets about EIGRP, redistribution, filtering and more.

Does this sound interesting to you? Take a look here and let me show you how to Master CCNP ROUTE




EIGRP Router ID Network Topology

Video Solution:

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Once you are logged in you will find the configuration files right here.

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The How to Master series helps you to understand complex topics like spanning-tree, VLANs, trunks, OSPF, EIGRP, BGP and more.

Written by René Molenaar - CCIE #41726

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About the Author: Rene Molenaar

René - CCIE #41726 is the creator of GNS3Vault.com where he shares CCNA, CCNP and CCIE R&S labs. He also blogs about networking on http://networklessons.com


  1. Can you give me a clue? Thought this would be easy but finding a bit difficult with out using filtering.

  2. Hi John,

    This is one of the EIGRP ‘gotchas’. If two EIGRP routers share the same router ID then your router will not accept any external prefixes. Try changing the router ID on the router(s) and you’ll find the answer 🙂


  3. Hi Rene,

    Greate…..OK I have done something different…I just deleted the redistribution from eigrp process and applied a new network statement for in spy router….Now when i checked the routing table in copy cat it shows the entry for….even both spy and copycat routers are having same router ID. So is there any problem for having same router ID for multiple routers in same EIGRP AS…??

    Thank You

    1. Good job that’ll work as well. Only when you redistribute prefixes into EIGRP a duplicate router ID is a problem. I didn’t think of this but it’s a valid solution if you ask me.

  4. This is a neat trick. I probably wouldn’t use it in the real world, but its very interesting. I was also able to accomplish the task by configuring “eigrp stub redistribution” command Imposter, but thats probably a form of filtering…

  5. You could also set the max hop-count for EIGRP to be 1 on the CopyCat router

    But just like bigtime813’s solution this can be argued to be a form of filtering.

  6. that’s nice, before checking the video I set a stub redistribute on router Imposter, Thank you rene every day you Teach something new, boodies I would recommed to buy the books and subscribe to Networklessons.com, Thanks for all your hel rene.

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