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IPv6 OSPF Virtual Link Sim

May 8th, 2014 in Lab Sim, LabSim Go to comments


TUT is a small company that has an existing enterprise network that is running IPv6 OSPFv3. However, R4’s loopback address (FEC0:4:4) cannot be seen in R1. Identify and fix this fault, do not change the current area assignments. Your task is complete when R4’s loopback address (FEC0:4:4) can be seen in the routing table of R1.


Special Note: To gain the maximum number of points you must remove all incorrect or unneeded configuration statements related to this issue.

Answer and Explanation:

To troubleshoot the problem, first issue the show running-config on all of 4 routers. Pay more attention to the outputs of routers R2 and R3

The output of the “show running-config” command of R2:


The output of the “show running-config” command of R3:


We knew that all areas in an Open Shortest Path First (OSPF) autonomous system must be physically connected to the backbone area (Area 0). In some cases, where this is not possible,we can use a virtual link to connect to the backbone through a non-backbone area. The area through which you configure the virtual link is known as a transit area. In this case, the area 11 will become the transit area. Therefore, routers R2 and R3 must be configured with the area area-id virtual-link neighbor-router-id command.

+ Configure virtual link on R2 (from the first output above, we learned that the OSPF process ID of R2 is 1):

R2#configure terminal
R2(config)#ipv6 router ospf 1
R2(config-rtr)#area 11 virtual-link

(Notice that we have to use neighbor router-id, not R2’s router-id

+ Configure virtual link on R3 (from the second output above, we learned that the OSPF process ID of R3 is 1 and we have to disable the wrong configuration of “area 54 virtual-link”):

R3#configure terminal
R3(config)#ipv6 router ospf 1
R3(config-rtr)#no area 54 virtual-link
R3(config-rtr)#area 11 virtual-link

We should check the configuration on R4:

R4#show running-config

You will see a wrongly configured virtual-link command. To get full mark we have to disable this command:

R4#configure terminal
R4(config)#ipv6 router ospf 1
R4(config-rtr)#no area 54 virtual-link

After finishing the configuration don’t forget to ping between R1 and R4 to make sure they work well!

Now all the configuration was done. It is weird that we can’t ping the IPv6 loopback interface of R4 (with the ping or ping ipv6 command) but we can check by using the command show ipv6 route on R1

The copying running-config startup-config command will not work but don’t worry, just skip it.

Notice: If you issue the command “show running-config” on R1, you will see these two lines:

passive-interface default
no passive-interface fa0/0 (fa0/0 is the interface connecting with R2)

These two lines make all the interfaces of R1 become passive interfaces except interface fa0/0. They are correctly configured so don’t try to disable them.


Other lab-sims on this site:

EIGRP Stub Sim


EIGRP OSPF Redistribution Sim

EIGRP Simlet
Policy Based Routing Sim

Comment pages
  1. @studdingalot
    September 13th, 2017

    All sims are similar to what you see on this website , but most of the multiple choice are different …loads of DMVPN , TCP/UDP , IPV6 and simlets

  2. mantuika
    September 29th, 2017

    Cool guy, the area between AREA-0 & AREA-54 is AREA-11. That is the transit area, not 54.

  3. Moreseas
    October 3rd, 2017

    Re: Cool-Guy
    Think of it this way; Area 11 is just fine because it has at least one router in the backbone area 0, the virtual-link command is technically merging area 54 with area 11 so as to satisfy the condition of having at least one interface in the backbone area. That is a good way to look at it.
    Let me know if this helps you

  4. Chikku
    October 29th, 2017

    Anyone who took the exam recently can confirm which are the SIMs in the exam?????
    I’m gonna take it early next week.
    Please respond asap.

  5. Dgo
    October 29th, 2017

    Thank you FRANKIE

  6. Dgo
    October 29th, 2017

    Just added all of the Labs into one big GNS3.. hit me up if you are interested>


  7. nowlad
    October 30th, 2017

    @ all, please help:

    When I do on R3: no area 54 virtual-link and on R4 no area 54 virtual-link

    Than I cannot ping FEC0:4::4 and I cannot see it with show ipv6 route ..

    Why? Is the GNS3 Lab wrong?? Please help

  8. hacker
    November 2nd, 2017

    about the show ip route on IPv6 OSPF virtual link. why FEC0:4::4 does not appear on R1. I follow all of the steps that written here on this site. PLEASE HELP..

    R1>show ipv6 route
    IPv6 Routing Table – 6 entries
    Codes: C – Connected, L – Local, S – Static, R – RIP, B – BGP
    U – Per-user Static route
    I1 – ISIS L1, I2 – ISIS L2, IA – ISIS interarea, IS – ISIS summary
    O – OSPF intra, OI – OSPF inter, OE1 – OSPF ext 1, OE2 – OSPF ext 2
    ON1 – OSPF NSSA ext 1, ON2 – OSPF NSSA ext 2
    L FE80::/10 [0/0]
    via ::, Null0
    C FEC0::/28 [0/0]
    via ::, Loopback0
    L FEC0:1::1/128 [0/0]
    via ::, Loopback0
    OI FEC0:2::2/128 [110/10]
    via FE80::C202:14FF:FEE4:0, FastEthernet0/0
    OI FEC0:3::3/128 [110/74]
    via FE80::C202:14FF:FEE4:0, FastEthernet0/0
    L FF00::/8 [0/0]
    via ::, Null0

    R4#show ipv6 route
    IPv6 Routing Table – 7 entries
    Codes: C – Connected, L – Local, S – Static, R – RIP, B – BGP
    U – Per-user Static route
    I1 – ISIS L1, I2 – ISIS L2, IA – ISIS interarea, IS – ISIS summary
    O – OSPF intra, OI – OSPF inter, OE1 – OSPF ext 1, OE2 – OSPF ext 2
    ON1 – OSPF NSSA ext 1, ON2 – OSPF NSSA ext 2
    L FE80::/10 [0/0]
    via ::, Null0
    C FEC0::/28 [0/0]
    via ::, Loopback0
    OI FEC0:1::1/128 [110/84]
    via FE80::C203:14FF:FEE4:0, FastEthernet0/0
    OI FEC0:2::2/128 [110/74]
    via FE80::C203:14FF:FEE4:0, FastEthernet0/0
    OI FEC0:3::3/128 [110/10]
    via FE80::C203:14FF:FEE4:0, FastEthernet0/0
    L FEC0:4::4/128 [0/0]
    via ::, Loopback0
    L FF00::/8 [0/0]
    via ::, Null0

  9. Dim
    November 16th, 2017

    @hacker: Look the message from @frankie. Check Loopback0 on R1 and on R4 – they aren’t participate in an OSPF process.
    So add ip ospf 1 area 0 for L0 on R1 and ip ospf 1 area 54 for L0 on R4.

  10. Dim
    November 16th, 2017

    @hacker: Sorry, a little mistake in commands:
    ipv6 ospf 1 area 0 – on R1
    ipv6 ospf 1 area 54 – on R4

    show ipv6 ospf int – to check what interfaces are participating in an OSPF on this router for IPv6.

  11. LightStealer
    December 3rd, 2017

    @frankie @Dim. Do we need to change the area assignments on these loopbacks? As the instructions says, we are not allowed to change the area assignments.
    I changed the area assignments on the loopbacks and I can ping already. Is this true as well on the real exam? Or this lab has the wrong configuration?

  12. PTT
    December 4th, 2017

    @nowlad: Than I cannot ping FEC0:4::4 and I cannot see it with show ipv6 route ..

    -> you should type these command in R1’s int l0 and R4’s int l0
    interface Loopback0
    ipv6 ospf 1 area 54

    interface Loopback0
    ipv6 ospf 1 area 54

  13. LightStealer
    December 6th, 2017

    @frankie @Dim. Do we need to change the area assignments on these loopbacks? As the instructions says, we are not allowed to change the area assignments.
    I changed the area assignments on the loopbacks and I can ping already. Is this true as well on the real exam? Or this lab has the wrong configuration?

  14. Anonymous
    December 15th, 2017

    I still dont understand why we need to lo0 of R1 to be in area 0 in order to ping lo0 of R4

  15. Joe
    December 17th, 2017

    I have downloaded the lab from here , all the routers are empty from configuration. why?

  16. dumpspro
    January 26th, 2018

    latest dumps ccie 400-101


  17. ccnp83
    March 3rd, 2018

    how can i downgrade my gns3,i cant seem to open any of the GNS files shared due to version incompatibility,any idea please.I cant find old GNS3 versions anywhere.

  18. Jola
    March 6th, 2018

    any one have real exam GNS Lab Sim for all labs?

  19. Anonymous
    March 22nd, 2018

    can you provide me the IOS Image which can open this virtual link ospf lab in gns3. PLSSS

  20. Grash
    April 3rd, 2018

    I don’t know why R1 receive R2 and R3 loopback ip routes without configuring them in ospf process and it is needed to include R4 and/or R3 loopback interface in ospf process in order to receive in R3/R4. Any idea?

    Also, why it is not receiving R1 routes of Fastethernet of R4 or Serial of R3?

  21. Elv
    April 16th, 2018

    If you were not able to ping R1 loopback address then it means the loopback interface was not added to area 0.

  22. Jpar
    April 18th, 2018

    Could someone please help me with the CCNP route latest dumps.
    email :: jigar231@gmaildotcom

  23. NealCont
    May 14th, 2018

    ¿¿How do you ping between R1 and R4??

  24. mujib
    June 9th, 2018

    How to add ipv6 LOOPBACK address FECO:1::1 ON Cisco router
    can someone show me and email me on syedmr4 at yahoo.co.uk

  25. Anonymous
    June 19th, 2018

    hello mujib,

    on the very interface

    R1(config)#int f0/0
    R1(0nfig-if)#ipv6 ospf 1 area 0

    it just a example for you

  26. Anonymous
    July 20th, 2018

    had a weird experience in the exam with this lab: as soon as I took out the unneeded virtual-link between R4-R3, the neighbor adjacency went down yet the loopback from R4 would show up in R1. Even after the correct virtual-link came online, there were no Neighbor FULL status messages, yet if I put the unneeded virtual-link on there, I would get the syslog for Neighbor Full.

  27. rrr
    September 8th, 2018

    the sim for ipv6 ospf virtual-link dont work
    can you fix the probleme

    September 16th, 2018

    9TUT is the best. I see people asking for dumps here and there, others complaining about outdated questions. Worse, some other folks come here to advertise their unpopular websites (shame on you). Please STOP IT. For test takers :

    Exam questions are part of a pool of questions. Some questions have 2 or more reformulations, thus memorization will not help for all questions.

    – Read the official certification guide and understand the concepts (search cisco press articles to get deep knowledge on certain topics).

    – Do as much as labs you can. Familiarize with the output of the most important commands, the correlation between commands and the correlation of a command with the concepts.

    – Come on 9TUT and spend 2 to 3 weeks. Caution : I strongly believe that some questions do not have correct answers. Thus, I advise that you validate with further readings (this will also allow you to be ready with reformulated questions).

    Bingo, you got it. I passed with a score of 900 (3 sims : OSPF Virtual link, OSPF EIGRP Redistribution and EIGRP stub).

    For the redistribution, its a 3rd case (because there are 2 ethernet links : between R2-R3 and R2-R4). Traffic had to go via the shortest link. I applied the 9TUT Case 1 config.

    Good luck.

  29. kaleem
    September 17th, 2018

    IPV6 OSPF Virtual -Link lab

    Configuration of R4 as its stated that to get full marks disable this command
    area 54 virtual-link

    if we disable this we cannot ping from R1
    If we disable this command then There is interface loopback 0 we have to assign area 54

  30. Warfac3
    September 17th, 2018

    Final step should be R4#configt –R4#(config)interface looback 0 –R4(config-if)#ipv6 ospf 1 area 54

    once that is done R1#show ipv6 route (FEC0:4::4 should now show up in the routing table)

  31. Anonymous
    September 18th, 2018

    interesting test i did and found another possible solution, just make area 11 a virtual link:

    On R2:
    area 11 virtual-link

    On R3:
    area 11 virtual-link

    For this to work R4 would have to have its Loopback interface in a different area and would have to have area 54 configured as a virtual-link, but since R4’s config is not shown can’t know for sure.

    So check R4’s config for the following:

    interface loopback 0
    ipv6 ospf 1 area 55
    ipv6 router ospf 1
    area 54 virtual-link

    if they exist on R4, just add the area 11 virtual-link on R2 & R3. After that R4’s loopback will show in R1 routing table and pings will work!!!

  32. Arroyo Grande
    September 18th, 2018

    Hi, unfortunately I have failed the exam. Used the pass4sure material that can be renamed to fail4sure! If you are thinking on purchase these material, you better think twice.

    The labls are quite the same. Just do the labs from here and you will be ready to do the labs in the real exam.

    There are a lot of questions related to Frame-relay LMI, NAT-PT, NAT64, ACLs , A/A/A, mGRE, uRPF loose/strict and EVN.

  33. Anonymous
    September 19th, 2018

    is there issue with the lab as with above instructions we dont see the route added

  34. Picklepants
    September 27th, 2018

    I agree the GNS3 lab doens’t work if the basic virtual link commands listed here are done.
    you have to add the L0 on R4 and L0 on R1 to ospf to make the routes appear and be pingable.
    is this the same in the actual exam? or is this just a GNS3 Bug?

  35. HansPeru
    October 12th, 2018

    Dear Guys,
    Yesterday I passed with 8XX the exam 300-101!! and this question was in the exam, regards from Peru.

  36. Nongshim
    October 13th, 2018

    @HansPeru Did you remove the virtual link on R4 and put loopback 0 in area 54 so the pings from R1 to R4 would work?

    Or is the answer from digital tut correct as it is and there is no need to do anything further on R4 loopback?

  37. HansPeru
    October 15th, 2018

    It was not necessary to add R4 loopback to 54 área (already it was in the configuration), so the loopback of R4 must be in area 54

  38. Nongshim
    October 15th, 2018

    @HansPeru So did you just use the configuration answer from digitaltut? Was there anything extra you had to do?

  39. CCNP-Nuggets
    December 5th, 2018

    I had this sim today, realized that the exam did not allow me to conduct ping from R1 to R4 or vice versa. We will need to ensure R4 Lookback is in R1 IPv6 Routing table (show ipv6 route). Above exam is enough to pass this question.

  40. CCNP
    December 7th, 2018

    Hi guys,

    today I had the exam, passed it with 900.
    There were about 15 to 20 new questions.
    More than 7 Frame-Relay.
    It’s not enough to just concentrate on pools but it helps.
    It needs to understand the concepts and little more.

    Labs were the same. No changes.

    OSPF Virtual Link
    OSPF Sim
    EIGRP Stub Sim

    Thanks digitaltut.
    Thank you guys.

  41. Gns
    December 10th, 2018

    @ CCNP how do you configure th OSPF virtual link?

  42. Yahya
    December 11th, 2018

    I do ping from from R4 to R1 but it is not success, then I advertised the Loopback IPv6 of R1 in Area 0, then the ping success

  43. Mahmoud
    December 15th, 2018

    missing conf on R1 & R4…that will make routes of R4 appear in R1
    & R1 appear in R4

    R4(config)#int loopback 0
    R4(config-if)#ipv6 ospf 1 area 54

    R1(config)#int loopback 0
    R1(config-if)#ipv6 ospf 1 area 0

  44. thing
    December 17th, 2018

    The 300-135 and 400-101 subjects are now stable, the latest update, and the people who passed the two days passed. Proshosts.com

  45. Yahya
    December 18th, 2018

    I configure IPv6 address and adverised it on R1 then the ping from R1 to R4’s loopback success

  46. Anonymous
    December 20th, 2018

    Took the test. Had this lab. But here is the strange part, R1, R2, R3 and R4 ethernet interfaces were configured with ipv6 addresses, however, interfaces (Serial) between R2 & R3 are configured only with ipv4 address, not ipv6. I tried configuring ipv6 autoconfig on the serial interfaces, but it wouldn’t take the command. Did anyone else notice that the Serial interfaces were using ipv4 addresses? Looking at the configs I did not notice any type of translation being used between ipv4 and ipv6.

  47. anduda
    December 20th, 2018

    Hello everyone,
    Anyone have CCNP route dump can please help to send me at gmail:
    . I will be very appreciate and thanks a lot. Thank you.

  48. Nuts
    January 7th, 2019

    does anyone have an answer to Anonymous Question on Dec 20th 2018??

  49. BRakesh
    January 8th, 2019


    did you try to configure a tunnel? or notice if there any tunnel or similar technology already in congif in exam?

  50. Megane
    January 10th, 2019


    What I have noticed is that these are only simulations, not using the real IOS. So I took the exam, it had an ospf sim/lab. R1 needs to be able to ping loopback on R4, but initially you can’t ping R4 loopack. The loopback of R4 was shown on the screen for your reference, but I initially didn’t notice it, so to get the loopback ip, I clicked on the console for R4 and did a “sh ip int brief” to get the loopback ip, but there was NO loopback interface configured at all, then I finally noticed the loopback ip address shown on the screen (just below the summary description of the problem). So I figure, ok, I need to configure the loopback on R4. So on R4 I type “configuration terminal” and hit enter, but then I got a pop up box that said “Error, This configuration cannot be changed”. I thought that there was an issue with the test itself. So I tried to log into the other routers and there I was able to log into config t mode without any issue. So again I thought that there was something wrong with the test itself and I was about to go get the person who worked there to show him. But then on R4 I did a “show run” and in the config the loopback address was already configured. The simulation simply did NOT show the loopback interface or ip address when doing a “show ip int brief” (even though it showed the ethernet/serial interface and its ip address). So on R1 and R2 I just had to configure ospf and then I was able to ping R4.

    So the moral of the story is, these sims are not real. If someone saw ipv4 addresses between R2 and R3 and no ipv6 address was configured and no translation was being done and no one else commented that they had to configure ipv6 addresses between R2 and R3, then more than likely, the ipv4 addresses were just a mistake that has no affect on whether you can get the virtual command/sim to work correctly. But this is something good to know, cause you could easily freak out and waste time if you don’t see something right, even though it really doesn’t affect your ability to do the sim.

    The webmaster of this page should take what I’m saying and post it at the top of the lab sims and basic labs page so people are aware that this occurs on cisco’s tests.

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