• Basic EIGRP *Break Fix*

    Posted on March 10, 2012 by in Tutorials

    EIGRP (Enhanced Interior Gateway Routing Protocol)

    One of many routing protocols available for us to use and this (this is a cisco proprietary protocol though), so you won’t find it on your HP switches.

    I won’t go too much in to the detail behind EIGRP as I could go on all day and all night, and that isn’t what this post is about. This post assumes you have a basic understanding of EIGRP, and will show you how to configure and trouble shoot EIGRP at a very simple level.

    Now EIGRP in itself is pretty damn easy to configure, lets take the below network:

    We have a basic setup of 3 routers, all connected via the serial ports. Each router R1 and R3 run off to a switch, which have 3 computers hanging off it. The two networks connected to R1 are 192.168.1.0/24 and 1.1.1.0/30. For R3 it’s 10.10.10.0/24 and 2.2.2.0/30

    Before we start configuring the router, let do a quick show ip route on Router 1 and take a look at it’s routing table :

    1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks

    C 1.1.1.0/24 is directly connected, Serial0/3/0
    C 1.1.1.2/32 is directly connected, Serial0/3/0
    C 192.168.1.0/24 is directly connected, FastEthernet0/0

    The only networks Router 1 knows are those which are directly connect to it. Which makes sense! Now lets get on with the configuration

    First we are going to get on to R1 and do the following:

    • router eigrp 5
    • no auto-summary
    • network 1.1.1.1 0.0.0.3
    • network 192.168.1.1 0.0.0.255
    • end

    This is telling R1 to use EIGRP as it’s routing protocol using the ASN (autonomous system number) of 5 (this MUST at either end), and to advertise the two networks. (you will notice a wilcard mask after the IP address, if you don’t know what Wildcard masking is google it, or I’m sure I will cover it later on at some point!).

    We now move on to R3:

    • router eigrp 5
    • no auto-summary
    • network 2.2.2.2 0.0.0.3
    • network 10.10.10.1 0.0.0.255
    • end

    We now have R1 and R3 setup and ready to go. finally we need to configure R2, I have included the output which will be displayed on the screen as you type the network command in as once you press return this will form an adjacency with it’s neighbor:

    • router eigrp 5
    • no auto-summary
    • network 1.1.1.2 0.0.0.3 *%DUAL-5-NBRCHANGE: IP-EIGRP 5: Neighbor 1.1.1.1 (Serial0/3/0) is up: new adjacency*
    • network 2.2.2.1 0.0.0.3 *%DUAL-5-NBRCHANGE: IP-EIGRP 5: Neighbor 2.2.2.2 (Serial0/2/0) is up: new adjacency*
    • end

    Now that this is done if we move back over to R1 and do a show ip route we will see the routing table is now populated with networks learnt via EIGRP:

    R1#show ip route 
    Codes: C - connected, D - EIGRP, EX - EIGRP external

    1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
    C 1.1.1.0/24 is directly connected, Serial0/3/0
    C 1.1.1.2/32 is directly connected, Serial0/3/0
    2.0.0.0/24 is subnetted, 1 subnets
    D 2.2.2.0 [90/21024000] via 1.1.1.2, 00:00:17, Serial0/3/0
    10.0.0.0/24 is subnetted, 1 subnets
    D 10.10.10.0 [90/21026560] via 1.1.1.2, 00:00:17, Serial0/3/0
    C 192.168.1.0/24 is directly connected, FastEthernet0/0

    If we now try to ping from a PC with the IP: 192.168.1.5 to 10.10.10.6 we get the following:

    Pinging 10.10.10.6 with 32 bytes of data:

    Request timed out.
    Reply from 10.10.10.6: bytes=32 time=19ms TTL=125
    Reply from 10.10.10.6: bytes=32 time=22ms TTL=125
    Reply from 10.10.10.6: bytes=32 time=23ms TTL=125

    Ping statistics for 10.10.10.6:
    Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),

    REMEMBER - do NOT worry if the first ping times out as what is happening if it’s the first time you are pinging a device? Thats right it’s “ARP’ing” (if you don’t know what it is google it! or i’ll cover it later on at some point).

    So there we have it, a simple EIGRP setup. Took what less than a minute to configure?

    I’ve included a break fix lab as well so not only can you configure it for yourself, you can have ago at fixing the lab i’ve proviced (enable password: michael) and the solution can be found if you scroll to the bottom right.

    EIGRP 3 Routers 6 PCS

     

3 Responses so far.

  1. Dolbow says:

    Thank you for the post.

  2. Lebron says:

    Thanks for another informative post.

  3. Jeremy says:

    Great post


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