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OSPF Questions

November 4th, 2018 Go to comments

Note: If you are not sure about OSPF, please read our OSPF Tutorial.

Quick OSPF review

– OSPF is a link-state routing protocol, which runs Dijkstra algorithm to calculate the shortest path.
– Link-state routing protocol like OSPF has a common view of entire topology
– OSPF only uses bandwidth to calculate metric.
– Area 0 is called the backbone area
In order to become OSPF neighbor, the following values must be matched on both routers:

+ Area ID
+ Authentication
+ Hello and Dead Intervals
+ Stub area Flag
+ MTU Size

– Hello packets of OSPF are multicast to

Question 1

Question 2

Question 3

Question 4


In order to become OSPF neighbor following values must be match on both routers:

+ Area ID
+ Authentication
+ Hello and Dead Intervals
+ Stub Flag
+ MTU Size

Therefore we need to adjust the MTU size on one of the router so that they are the same. Or we can tell OSPF to ignore the MTU size check with the command “ip ospf mtu-ignore”.

Question 5


D is correct because these entries must match on neighboring routers:

Hello and dead intervals
Area ID (Area 0 in this case)
– Authentication password
– Stub area flag

In this case Ethernet0 of R1 has Hello and Dead Intervals of 5 and 20 while R2 has Hello and Dead Intervals of 10 and 40 -> R1 and R2 cannot form OSPF neighbor relationship.

Question 6


The information available to a distance vector router has been compared to the information available from a road sign. Link state routing protocols are like a road map. A link state router cannot be fooled as easily into making bad routing decisions, because it has a complete picture of the network. The reason is that unlike the routing-by-rumor approach of distance vector, link state routers have firsthand information from all their peer routers. Each router originates information about itself, its directly connected links, and the state of those links (hence the name). This information is passed around from router to router, each router making a copy of it, but never changing it. The ultimate objective is that every router has identical information about the internetwork, and each router will independently calculate its own best paths.

Reference: http://www.ciscopress.com/articles/article.asp?p=24090&seqNum=4

Question 7

Explanation belongs to subnet (range from to so the router will use FastEthernet0/1 as the exit interface.

Question 8


A is not correct because the backbone area of OSPF is always Area 0.
B is not correct because R1 or R3 must be the DR or BDR -> it has to establish neighbor adjacency with the other.
C is not correct because OSPF neighbor relationship is not established based on static routing. It uses multicast address to establish OSPF neighbor relationship.
E is not correct because configure EIGRP on these routers (with a lower administrative distance) will force these routers to run EIGRP, not OSPF.

D and F are correct because these entries must match on neighboring routers:

Hello and dead intervals
Area ID (Area 0 in this case)
– Authentication password
– Stub area flag

Question 9


The most obvious thing in this configuration is R1 forgot to run OSPF on interface Fa0/0 (with the “network area …”) command so the computers behind network does not know how to reach resources on a remote network.

Question 10


The well-known formula to calculate OSPF cost is

Cost = 108 / Bandwidth

so B is the correct answer.

Comments (50) Comments
  1. supunit21
    February 6th, 2017

    where are questions?

  2. Lucky
    February 8th, 2017

    Questions are Missing, Admin ?

  3. kk
    February 26th, 2017

    where are the questions ??

  4. Mr. Fisher
    March 10th, 2017

    There is no questions, where is it?!

  5. skyflakes
    March 12th, 2017

    find in other links, there is a pdf file in this 1. maybe in the share your ccna experience page.

  6. banay
    March 14th, 2017

    @supunit21 @Lucky @kk
    here you the link for the Questions


  7. waqas
    April 18th, 2017

    Plz some1 forward me 171 & 191 qs dums at waqas.uetpeshawar at gmail dot com. thanks in advance

  8. waqas
    May 5th, 2017

    passed ccna exam today (886/1000), nothing was really difficult.
    two labs there
    1). ACL
    2). EIGRP (little changes in topo)
    i read a lot of dump’s (545/719/182/266/473) but i would suggest prepare 719 and just go through 266, most of the questions there.
    GOOD LUCK!!!!

  9. Whoa!!!
    May 6th, 2017

    Q4 why answer is E and not D since as the explanation said, MTU and cost must match to established adjacencies. And AFAIK the default MTU is 1500. Need comment please

  10. Whoa!!!
    May 6th, 2017

    I mean why E instead of C?

  11. Anonymous
    May 29th, 2017

    Does anyone have the dump or questions for 266 and 719

  12. froggen
    June 8th, 2017

    @ woah. OSPF doesn’t need matching costed links to establish a neighbor relationship.

  13. duck
    June 8th, 2017

    Isnt the answer to question 13 supposed to be enable IPv4 to the F0/0 interface? I have seen that answer as being correct on other dumps. In the output it states ‘Ipv6 enable’. Any thoughts, @9tut ?

  14. Richard
    June 28th, 2017

    Passed today, can confirm this dumps as valid till now http://congressreiki.ranm.org/?all=basic-questions/comment-page-2#comment-3442171

  15. SsS
    July 12th, 2017

    what is the correct answer of Q3 please

  16. Anonymous
    July 16th, 2017

    @9tut – Could you please conmfirm the Question 13? Someone mentioned that the answer should be the –
    A. Configure a loopback interface on R1..

  17. Anonymous
    July 16th, 2017

    Sorry the Q-13 should be the – C. Configure an IPv4 address on interface Fa0/0. Is it correct?

  18. m1987
    August 5th, 2017

    Bis the right one because:
    In OSPF you have process id and areas, for EIGRP you have AS witch should match
    IPv4 addresses are needed for the Router to set router-id but from what i can see the ID is set manualy.
    ‘Configure a loopback interface on R1, i don’t see the need to do so

  19. Anonymous
    August 7th, 2017

    Q13 it’s not the correct answer

    in have try to introduce that comand and the IOS do not let you to ingress to ipv6 router configuration mode if you have not configure the ipv6 unicast-routing before.

    So in this picture we have to supose that ipv6 unicast-routing is issue yet.

    R1(config)#ipv6 router ospf 1
    % IPv6 routing not enabled

  20. Rudhra
    August 12th, 2017

    Does anyone have recent dumps?

  21. Rudhra
    August 12th, 2017


  22. Amir
    August 13th, 2017

    I have latest cisco exam with Printable PDF + Premium VCE + VCE Simulator.

    Email : {email not allowed}

  23. Amir
    August 13th, 2017

    I have latest cisco exam with Printable PDF + Premium VCE + VCE Simulator.
    If you want send me telegram pm


  24. Rudhra
    August 15th, 2017

    @amir can you tell me how I can get latest dumps?

  25. Ugo
    September 5th, 2017

    Thanks guys your contributions to this platform has been helpful.

  26. Alvin
    September 15th, 2017

    Can i get the latest dumps?

  27. Mark
    September 27th, 2017

    This are the dumps that I am studying from now https://drive.google.com/open?id=0B5mAFqgydmCzUWJPTTFkemFuQTA

    I think this dumps and tut is enough .

  28. mARTIN
    November 7th, 2017

    Mark would you please allow as to edit the files

  29. cisc0M
    January 12th, 2018

    Refer to the exhibit. You have discovered that computers on the network can ping their default gateway, but they cannot connect to any resources on a remote network. Which reason for the problem is most likely true?
    R1 interface Loopback0 ip address interface FastEthernet0/0 ip address interface FastEthernet0/1 ip address ! router ospf 1 router-id network area 0 network area 0
    A. The network is missing from OSPF.
    B. The OSPF process ID is incorrect.
    C. The OSPF area number is incorrect.
    D. An ARP table entry is missing for
    E. A VLAN number is incorrect for

    all other websites say answer is ospf area number is incorrect…

  30. cthelite
    January 17th, 2018

    Q3: shows answer as C & D. Why not D & E ? I agree that the OSPF algorithm puts a higher strain on routers, so D sure. But OSPF does have a TOP TABLE, and it obviously does have all advertised routes from which to choose to put in the routing table… “large” may be a matter of opinion, but having all routes would indicate substantial size compared to other routing protocols. So “E” seems to be the most correct. “C” could be said for any routing protocol? But “E” seems to be the best 2nd answer.

    The deeper I get into these questions on 9tut, the more confusing the questions and answers and I’m not seeing much guidance on what are correct answers, or even if the questions are correct?! I can appreciate the investigative aspect of finding the answers, but ultimately it would be nice to know what the correct answer actually is… if the CCNA exam is actually this ambiguous, I’m in trouble.

  31. cthelite
    January 17th, 2018

    OK, so I finally found an argument against “E”. I consider “TOPOLOGY TABLE” in a broad perspective which is the same as “ospf database”, it is the same in function! But I guess Cisco considers it a “Cisco term”, and “ospf database” an OSPF term. So for the sake of this question, Cisco does not agree OSPF has a “topology table”.

    I still think “C” is a best practice which would apply to ALL routing protocols, but if the above is accurate, it becomes the best 2nd answer.

  32. Is this the link to download the dumps ?
    February 2nd, 2018

    In question 4 network is advertised as If it is slash 31 then how come each of these hosts can be assigned IP addresses. Plus mtu nd cost should match on each router to form adjacencies so this explanation and answers are wrong. unequal load balancing is supported only in eigrp that too with variance command

  33. cthelite
    April 5th, 2018

    RE: Q4, COST does NOT need to match to form OSPF adjacency. Thus C is not correct. B wouldn’t match with even the new value, so it’s not correct. The mask and IPs are hokey, but simply changing the mask wouldn’t fix any problem, the IP of G0/0 would have to change also, so A is not correct. The explanation by 9tut is correct for the correct answers, D and E.

  34. Shariq
    May 8th, 2018

    waqas/anyone else,

    kindly share latest dumps , my exam is due 2 weeks later

    Email: shariqlp (at) gmail

  35. Anonymous
    June 1st, 2018

    Question 4.

    The network doesn’t have available hosts to assign IP addresses to the router interfaces.
    I think the question has some mistakes

  36. ze123
    August 7th, 2018

    how can I get dump of questions?

  37. blabla
    October 3rd, 2018

    Q7: “” address belongs to and belongs to, also it belongs to Im right? So if im right you need to check for OSPF cost [110/2], [110/11] and [110/2] for third route. You can see that all are OSPF routes and cost of 2 will be chosen but there are two routes with cost of 2. So you router will choos “most precise” route that means subnet mask with higher prefix. Can someone check this and explain this question if im wrong?

  38. moin
    October 18th, 2018

    Q3 @cthelite
    Cisco does talk about a OSPF topology table:
    “To display the Open Shortest Path First (OSPF) topology table, use the show ip ospf routes command.”

    OSPF drawbacks normally are stated as memory and CPU requirements:

    “The disadvantage of shortest path first algorithms is that they require a lot of CPU cycles and memory.”

    Dividing an internetwork into areas is a response to three concerns commonly expressed about link state protocols:
    The necessary databases require more memory than a distance vector protocol requires.
    The complex algorithm requires more CPU time than a distance vector protocol requires.
    The flooding of link state packets adversely affects available bandwidth, particularly in unstable internetworks.
    – Routing TCP/IP Volume I

  39. Anonymous
    November 9th, 2018

    Hi, where do you find the questions?

  40. Anonymous
    November 13th, 2018

    please share the link to questions.

  41. Plypots
    December 21st, 2018

    Question 4.

    Why is one of the routers using a broadcast address? More Cisco BS!

  42. ssh
    March 29th, 2019

    Hi, can anyone send the latest dumps? ({email not allowed}) I’m going to take the exam in April. Thank you very much

  43. bill
    May 9th, 2019

    ssh, how did exam go?

  44. Shippu
    May 10th, 2019
  45. Podranok
    October 26th, 2019

    Q4. There is a mistake made in picture regarding addresses between P2P routers. For addresses are .0 and .1 with “ip subnet-zero” global command. For .254 and .255 network would be It is OSPF so you do no need BROADCAST to establish adjacency.
    Anyway, MTU matching explanation is correct.

  46. moy
    December 24th, 2019

    cand someone send me the latest dumps {email not allowed}

  47. Q4
    January 1st, 2020

    Padranok’s Explanation (October 26th, 2019) for the answer is correct. Please refer to it to clarify any doubts

  48. Ariel
    January 19th, 2020

    Q7, en este caso no debería elegir las rutas con menor costo? Y de las dos rutas con menor costo (2) la más precisa, en este caso la interface de salida F1/0? Podría alguien explicarme si estoy en lo cierto o no?

  49. Q8
    January 23rd, 2020

    Question 8

    R1 is unable to establish an OSPF neighbor relationship with R3. What are possible reasons for this problem? (Choose two)

    A. All of the routers need to be configured for backbone Area 1.
    B. R1 and R2 are the DR and BDR, so OSPF will not establish neighbor adjacency with R3.
    C. A static route has been configured from R1 to R3 and prevents the neighbor adjacency from being established.
    D. The hello and dead interval timers are not set to the same values on R1 and R3.
    E. EIGRP is also configured on these routers with a lower administrative distance.
    F. R1 and R3 are configured in different areas.

    Answer: D F


    E is not correct because configure EIGRP on these routers (with a lower administrative distance) will force these routers to run EIGRP, not OSPF.

    With this explanation correct answers should be D and E. Looking the pictures R1 and R3 ARE in the same area (area 0)

  50. Scourge
    January 23rd, 2020

    @9tut please check Q8 (post below, i missed name before, sorry!)

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