EIGRP IP Default Network

Posted by December 9, 2010 in EIGRP

Scenario:

As the network engineer for your Cisco-only network you run into a strange problem. Some of the routers have been replaced and have empty configs and per configuration template you need to configure EIGRP IP Default Network. Some of the older routers still run IGRP and are unable to advertise default routes, in order to keep all configs on routers the same you are forced to use the older “IP Default Network command”. One of your colleagues still has an output from an old “show ip route” command which will show you what you need to achieve.

Goal:

  • All IP addresses have been preconfigured for you.
  • Configure EIGRP AS12 as following:
    – Do not disable auto-summarization.
    – Advertise network 172.23.23.0 /24
    – Advertise network 10.12.12.0 /24
    – Do not use any other network commands.
  • You have completed this lab when you see the following when you type “show ip route” on router Erik:

 Gateway of last resort is 10.12.12.2 to network 172.33.0.0

 

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IOS:

c3640-jk9s-mz.124-16.bin

Topology:

EIGRP IP Default Network

Video Solution:

Configuration Files

You need to register to download the GNS3 topology file. (Registration is free!)

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

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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

16 Comments

    1. Like Rene said, you can use most other routers but you have to change the path for the image inside of the topology file (in this lab it’s called EIGRP IP Default Network.net) .
      So, in my case the image is located on c:\gns3\images\your_image_file_name.bin . Once you do this, you need to restart the topology again. You also need to change the path to the configs… in this case the config path in the original file says EIGRP IP Default Network_configs/R1.cfg for example on router 1.. but since i’m running windows I need to have that forward slash (/) changed to a back slash (\).

      This should make things work for you.
      Good luck!

  6. Hello Tosin,

    I can’t help you with finding an IOS but any 3600, 3700 or 7200 image will let you run EIGRP so it doesn’t matter which one you’ll use.

    Good luck!

    Rene

  7. Hi,

    we can use

    [b]Jan(config-router)#redistribute connected[/b]

    then

    [b]Jan(config)#ip default-network 172.33.0.0[/b]

    thanks

    1. That will work, you can also do this:

      [code]ip route 0.0.0.0 0.0.0.0 null0[/code]

      [code]router eigrp
      network 0.0.0.0[/code]

  8. Rene,

    I noticed that the ip default-network seems not a requirement to be able to ping from erik to loopback of JAN.
    When i left it out it still worked but i did not have the default gateway set on erik and Lisanne when doing so.

  9. i used in router Lissanne:

    router eigrp 12
    redistribute static
    network 10.12.12.0 0.0.0.255
    network 172.23.23.0 0.0.0.255
    auto-summary

    ip default-network 172.33.0.0
    ip route 172.33.0.0 255.255.0.0 172.23.23.3

    if i use a redistribute connected does not work.?, i do not why..

    Regards.

    David,

  10. Hi !
    when i try to type the command (config)#ip default-network 172.33.0.0 in router Jan or router Lisanne still i can see they Gateway of last resort is 10.12.12.2 to network 172.33.0.0 in router Erik ,i am little bit confuse what is the diffrence between the solution in video ?

  12. Found one strange thing. This lab doesn’t work with IOS 15, but with IOS 12.4 it does!
    In IOS 15 gateway of last resort won’t be set, despite candidate-default network is present in routing table.
    Something has been changed between 12.4 and 15 IOS.

  13. This also works,
    [b]Jan(config)# int s0/0
    Jan(config-if)# ip summary-address eigrp 12 0.0.0.0 0.0.0.0[/b]

  14. Easiest method :
    Jan:
    router eigrp 1
    network 172.23.23.0 0.0.0.255
    network 172.33.0.0
    auto-summary
    !
    ip default-network 172.33.0.0

    On Erik will be appeared:
    Gateway of last resort is 10.12.12.2 to network 172.33.0.0

    D* 172.33.0.0/16 [90/2300416] via 10.12.12.2, 00:03:26, FastEthernet0/0

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