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BGP Prefix-Based Filtering Lab Sim

Question

After the network administrator modified the configuration on the WGR1 router, the WGR1 router is not able to receive any prefixes from AS22. The network administrator original intent was to only filter out a particular prefix from AS22.

Fix the configuration on the WGR1 router to solve the problem. You have correctly solved the problem once the WGR1 router is able to receive 23 prefixes from AS22.

Enable secret password is cisco

Prefix_Based_BGP.jpg

 

Answer and Explanation

First check the configuration of this router with the “show running-config”

WGR1# show running-config

We should also check the ip prefix-list configuration with the “show ip prefix-list” as well:

Currently we are not sure what you will see when typing these two “show” commands but we guess it can be something like this:

WGR1# show ip prefix-list
ip prefix-list 1: 1 entries
seq 5 deny 10.0.0.0/8

(Note: 10.0.0.0/8 is just an example)

The problem here is that there is always an implicit “deny all” entry at the end of each prefix-list. If the packet doesn’t match any entry of the prefix-list, it will match the implicit “deny all” and the packet will be filtered out.

Therefore we have to permit all packets with the command:

WGR1#configure terminal
WGR1(config)#ip prefix-list 1 seq 10 permit 0.0.0.0/0 le 32
WGR1(config)#exit

The “/0” part says “check 0 bit” of “0.0.0.0”; meaning that I don’t care what any of the bits are.  The “le 32” part says that the subnet mask can be 32 bits or less (down to the number of bits we are checking) -> down to 0. So we aren’t going to check any bits and the network can have a subnet mask of anything between 0 and 32 bits. This would be ‘any’.

Force BGP to clear its table and reset all BGP sessions:

WGR1#clear ip bgp *

Display the status of all BGP connections

WGR1#show ip bgp summary

WGR1#copy running-config startup-config

Categories: Lab Sim Tags:
  1. boom_zoom
    April 16th, 2011 at 01:45 | #1

    in the show runn output, the prefix config is exactly this below:
    !
    ip prefix-list 1 seq 5 deny 10.0.0.0/8
    !

    your example output above about show ip prefix-list is exactly the same exact output during the lab.

    you need to run the show runn command and show ip prefix-list command so that you can reference your config from there…

    you can also do show ip bgp summ before doing the config so that you can see that the neighbor x.x.x.14 is having no/zero (0) prefix entry.

    clear ip bgp * -is part of the lab because the changes wont take place without doing this. this also applies in real life.

    and of course, always always always do copy run start. its very impt.

  2. sarkar
    May 10th, 2011 at 04:05 | #2

    Nice to see that

  3. follower of iptut- a great website for learning
    May 24th, 2011 at 13:09 | #3

    Thanks for the explanation…this is too good.

  4. Anonymous
    June 8th, 2011 at 10:53 | #4

    Hi friends,

    Just two days back I completed my CCNA exam…now planning for CCIP ROuting paper…

    For to start, please point/suggest me what materials should I read..

  5. Rav
    June 8th, 2011 at 10:54 | #5

    Hi friends,

    Just two days back I completed my CCNA exam…now planning for CCIP ROuting paper…

    For to start, please point/suggest me what materials should I read..

  6. Zo3FoL
    June 18th, 2011 at 10:47 | #6

    @Rav: For ROUTE exam go to digitaltut.com.

  7. CCIP
    August 22nd, 2011 at 07:38 | #7

    973/1000. passed today. Thanks IPTUT. All questions from DODO.

  8. Don
    August 27th, 2011 at 12:38 | #8

    i scored 1000/1000 today 🙂 thanks for iptut and all guys here.

    Dodo still valid 10000%

  9. Kshitij
    September 6th, 2011 at 10:22 | #9

    I have passed today 1000/1000
    Thanks iptut!!!

  10. pkB
    September 18th, 2011 at 03:14 | #10

    hI PLEASE LET ME KNOW WHETHER ONLY ONE LAB !!!!

  11. dm
    October 11th, 2011 at 13:48 | #11

    please can someone give the link to download the bgp+mpls lab

  12. dm
    October 11th, 2011 at 13:49 | #12

    or email me d_mozoka@yahoo.fr

  13. Redhat
    November 9th, 2011 at 03:57 | #13

    i would like to ask your help on where i can download practice exam for qos 642-642

  14. saleem
    November 9th, 2011 at 10:39 | #14

    Asalam alaikum..any one give me a gns file of this labb???

  15. Sriram
    December 13th, 2011 at 05:51 | #15

    Hi All.

    This simulation is valid.
    i cleared with 960.
    Copy run start working

    Thanks all

  16. zooo
    December 15th, 2011 at 13:58 | #16

    Thanks
    Sriram

    what dump is valid now .
    i am take exam after tomorrow

  17. exploited
    December 19th, 2011 at 22:48 | #17

    Hi there I will take this on 21st Dec, I let you know about the dumps.

  18. orange
    December 28th, 2011 at 10:48 | #18

    hello all..could any one advise me if the dodo dumps are still valid…

  19. affy
    February 4th, 2012 at 06:12 | #19

    Hello guys,
    Can anyone mail me the latest dumps..
    I have an exam in 15 days.. plz mail the link @
    afaque213@gmail.com
    thank you

  20. JuanMa
    March 29th, 2012 at 01:53 | #20

    This lab is valid for the test.

    I have aprobed the exam yesterday.

    Another Labs are in Sadikhov, and are about Synchronization and ebgp-multihop.

    Without Testinside and this forum, the exam would be very very very dificult.

    Best Regards.

    Juan

  21. KD
    April 1st, 2012 at 20:36 | #21

    Guys I have given CCIP BGP Exam, would like to give MPLS as well…what is the major difference between the CCIP BGP+MPLS and CCIP MPLS? Is the combined one a toned down version?

  22. mangkiko
    April 5th, 2012 at 03:32 | #22

    JuanMama – yo mean their are more than 2 labs on your exam?? so this 2 here is not enough??

  23. Rizwn Younas
    April 5th, 2012 at 19:37 | #23

    i have exame after 15 days plz any one can mail me latest dumps rizwanyounas82@hotmail.com is main e main ID waiting ur prompt response.

  24. Anonymous
    April 23rd, 2012 at 13:30 | #24

    please help me i am gonna give my exam on 25th april ….

    WGR1
    neighbor 197.1.2.1 ebgp multihop

    ===========================
    WGR1

    ip prefix-list test seq 10 permit 0.0.0.0/0 le 32

    ===========================

    p1R3

    no synchronisaion
    neightbor 10.200.200.12 weight 255
    clear ip bgp * soft in

    i have a doubt is in or out in (clear ip bgp * soft ——–)
    ===========================

  25. leo
    April 25th, 2012 at 04:31 | #25

    Please share your exam experience,did you see any new simulation in BGP+MPLS exam?

  26. Slash
    May 29th, 2012 at 14:40 | #26

    i just passed the BGP + MPLS comp. exam today with a score of 1000/1000, the 99q dump is 100% valid, so are both labs.
    best of luck guys, and hurry as this exam will retire in July

  27. muneer
    May 31st, 2012 at 07:08 | #27

    hi Slash…
    i am planning to write MPLS can u please give details about dump (is it available in examcollection ? ) and about lab..

    thanks in advanc…

  28. Name
    June 7th, 2012 at 12:23 | #28

    Hi all, would you please sent the dump/pdf to dynamic.mineral@gmail.com please? cheers all

  29. Mafacho
    June 12th, 2012 at 05:39 | #29

    Hie guys does anyone have an idea where i can get Cisco CCNP Service Provider Operations Certification Exams Training Materials? if u do pliz kindly email me on f_makina@yahoo.com

  30. Alicia
    June 14th, 2012 at 20:36 | #30

    Ah, you misunderstand me heheI have to learn enugoh to do the hard versions of the exams anyway, so I’d prefer to use them as my check. The knowledge is what’s important to me, and the more questions I can answer that count’, the better off I think it is for me. Of course I have no incentive to take the easier path, work doesn’t care what certs I do, they won’t pay for any training, and so on, and management probably doesn’t realize it yet, but my coworkers certainly do once I pass the CCIE, I’m most likely gone. I don’t think management will be willing to pay the salary to keep two CCIE’s on staff, so I’m in no rush. I’m pretty much on a 2 year plan as it is. I’ve just never been a big fan of composite exams, I prefer to be able to focus my studies. Of course I might as well get used to the prospect, since the CCIE Written is really just one big Composite exam.

  31. Dheeraj
    June 29th, 2012 at 17:54 | #31

    hi…my mpls + bgp exam scheduled on 6th july. Can someone tell me if 99 Ques by piers on examcollection is valid…??

  32. Cisco cert
    July 12th, 2012 at 08:29 | #32

    I cleared the exam 1000/1000, the dumps DoDo are bulls eye.

  33. Nisha
    July 19th, 2012 at 07:19 | #33

    Can any one give me a gns file of this labb??? plsssss…

  34. SAHIL
    July 20th, 2012 at 05:04 | #34

    Hi, Guys can anyone tell me if these are the only 2 labs / sims coming in the exam or are there any more , anyone has seen ???
    Also are there any MPLS TE questions ??

  35. Mahmoud
    July 20th, 2012 at 13:27 | #35

    Hi , Please advise about DoDO and how can i get it ?

    Awaiting your assistance urgently as i’m going to exam after tomorrow , Thanks

  36. Pirlo
    July 20th, 2012 at 13:58 | #36

    Hi Mahmoud, go to examcollection.com, and serach for 642-691 exam dumps, you will find dodo there..

  37. boyi
    July 22nd, 2012 at 11:48 | #37

    @juanma
    (This lab is valid for the test.
    I have aprobed the exam yesterday.
    Another Labs are in Sadikhov, and are about Synchronization and ebgp-multihop.
    Without Testinside and this forum, the exam would be very very very dificult.
    Best Regards.
    Juan)

    i’m worry about this comment, is there any other labs apart of bgp and mpls for iptut?

  38. Thank you
    July 22nd, 2012 at 17:19 | #38

    How many labs are there for bgp and mpls in BGP + MPLS exam? Please reply

  39. boyi
    July 22nd, 2012 at 19:23 | #39

    @Thank you

    i thought only 2: bgp prefix list and mpls tdp, both from iptut. but this morning i saw the comment of @juanma talking about other labs. I’m very worried because i have to pass tomorrow. please anybody can confirm to us, if now only bgp and mpls labs from iptut are in the exam?

    thank you

  40. Mahmoud
    July 22nd, 2012 at 22:29 | #40

    Passed today with 1000/1000 , DoDo is 100 % Valid “with same answers order” and above 2 labs

  41. ZAR
    August 16th, 2012 at 09:23 | #41

    Hi guys, i have been using this site for all my exams, and it has been a lot of great help, as soon as i started with my CCNP SP, all the infor went dry for the certification, is anyone of you know here are can find CCNP SPADROUTE labs for this particular exam?

  42. Auth
    August 30th, 2012 at 00:04 | #42

    Yea, I’ve been quiet this week. I couldn’t work up the moiviatton to do that OSPF 2 walkthrough and I was slammed at work anyway.Funny thing about the last lab though, I didn’t really test anything with the tasks before I made them up, I just threw stuff down on paper and hoped I could figure it out. Some of it I couldn’t, lol. Stuff I thought would work didn’t, so twoish tasks in the lab weren’t possible (that I could see, if anyone figured all of it out, PLEASE let me know hah).So anyway, I figure I’ll try out the new idea. I like more interaction from this and the labs just didn’t seem to produce much.

  43. Gursharn
    October 20th, 2012 at 16:19 | #43

    Can anybody please tell whether DoDo and above 2 labs are still valid???

  44. Gursharn
    October 21st, 2012 at 14:23 | #44

    Can anybody tell me that where the latest dump and labs can be found for current BGP+MPLS (Cisco 642-691) exam???

  45. thuyein
    December 20th, 2012 at 08:08 | #45

    Plz,I want to study for CCNP service provider lab 642-883,642-885,642-887 ,642-889?

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