EBGP – External BGP

20 Comments

1. Thanks Uffe! It’s a simple network but it’ll teach you everything you need to know about EBGP.

2. Another great lab (Good job on sneaking in small problems, despite a few apparently simple goals – I wont post any spoilers 😉 )

3. Thanks, I’ll keep working until everything is at CCIE R&S level. I’ve been working on building new BGP labs and it will take some time to catch up with everything.

4. Thanks for making video. Pls keep making no matter basic or advanced. Good job

5. Hi Rene,

   I am unsure why the ebgp-mulithop was used in this exercise. What is the purpose of this command option? The iBGP lab used loopbacks as their neighbors but did not require using ebgp-mulithop. Can you please explain this for my understanding?

   Thank you,
   Bong

   1. Hello Bong,

      By default EBGP routers will send IP packets with a TTL of 1. This means you can only configure EBGP neighbor adjacencies using the IP addresses on the directly connected interfaces.

      If you want to configure EBGP between loopback interfaces you’ll need to use the EBGP multihop command.

      IBGP does not have this "restriction" so we don’t have to use a multihop command for this.

      Rene

6. nice..thank you 🙂

   1. You are welcome!

7. Why he’s using static route for step two and neighbor ebgp-multihop ????

   1. @ E_mad

      That part threw me for a loop also, I had the entire lab configured correctly and finally had to view the final config to see static routes were missing………. I will have to review the chapter and look for the info about using those staticroutes

8. Thank rane.. for such mathod of thech…. in books and lab… hope it has helped many people and will keep going on… thanks again

9. uhm rene, if we want to advertise directly connected network between two ebgp routers, should we advertise that network in both routers or not ?
   Thank you

10. Cant seem to find the way to download the topology file. Can anyone help please? Much appreciated.

    Thanks,
    _raymond

11. you have to register in this site after that you are able to download LABs

12. i did not have the exact IOS code version listed for this lab; therefore, i tried what i had.
    none of my c3640, c3725, or c3745 IOS code versions worked… kept getting “inaccessible” 2.2.2.2 and 3.3.3.3 between Flax and Silk respectively (even when i loaded the final configs from Rene).

    switched over to c7200 and everything worked fine LOL.
    just thot i’d share 🙂

    GNS3 version 0.8.3

    IOS versions that did NOT work for me:
    c3640-ik9o3s-mz.124-16b.bin
    c3640-ik9o3s-mz.124-25d.bin
    c3725-adventerprisek9-mz.124-15.T10.bin
    c3745-adventerprisek9-mz.124-15.T10.bin

    IOS version that DID work for me:
    c7200-adventerprisek9-mz.124-24.T8.bin

13. Hi Rene Molenaar,
    Please help me to clarify this point:
    At 6:21, after we “network 192.168.12.0 mask 255.255.255.0” on Wool router, we can ping 3.3.3.3 OK.

    Wool#ping 3.3.3.3

    Type escape sequence to abort.
    Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
    !!!!!
    Success rate is 100 percent (5/5), round-trip min/avg/max = 28/51/68 ms

    But before that, we can not ping 3.3.3.3 because Router Flax do not have knowlegde about network 192.168.12.0? That right?

    But when I use traceroute 3.3.3.3, the route stop at below:

    Wool#traceroute 3.3.3.3

    Type escape sequence to abort.
    Tracing the route to 3.3.3.3

    1 192.168.12.2 24 msec 64 msec 24 msec
    2 * * *
    3 * * *
    4 * * *
    5 * * *
    6 * * *
    7 * * *
    8 * * *
    9 * * *
    10 * * *
    11 * * *
    12 * * *
    13 * * *
    14 * * *
    15 * * *
    16 * * *
    17 * * *
    18 * * *
    19 * * *
    20 * * *
    21 * * *
    22 * * *
    23 * * *
    24 * * *
    25 * * *
    26 * * *
    27 * * *
    28 * * *
    29 * * *

    This mean route stop at router Silk?

14. Great lab Rene!! This is a great lab to learn the basics on eBGP.

    Thanks

    Eddie

15. Unfortunately it’s is impossible to start this new lab format. I tried arond 5-6 different images, it always either sticks at boot or is unresponsive. Please help. My CCNP route exam is in a week:))). Is there a way to download the old versions?

    1. Hi Alex,

       The old GNS3 0.8X topology files are here:

       http://gns3vault.com/forums/topic/gns3-0-8x-old-lab-topology-files/

       Rene

16. please help me to understand further. why the network 192.168.23.0/24 not being advertised by router Flax as well under bgp network command? why any network advertisement between two routers, is done by only one router for bgp? is this to prevent bgp loop mechanism?..appreciate your soonest reply on this as i will be sitting for ccnp exam.

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