Courseiva
← 200-301
Full test
Question 1,570 of 1,819
IP Routing →hardTroubleshootingObjective-mapped

Quick Answer

The answer is to correct the OSPF area and timer mismatches by adjusting R2’s G0/0 hello/dead timers to 10 and 40 seconds, and moving the 10.0.23.0/30 network statement to area 0. This is correct because OSPF adjacency requires matching hello and dead intervals on a link, as well as identical area IDs; R1’s timers of 10/40 conflict with R2’s 30/120, and R2’s G0/1 in area 1 cannot form an adjacency with R3’s G0/1 in area 0. On the CCNA 200-301 v2 exam, this tests your ability to troubleshoot OSPF neighbor failures using show ip ospf interface and show ip protocols, with a common trap being that changing timers on one side only breaks adjacency further—you must match both sides. A key memory tip is “Hello and Dead must be said in the same head”—timers and area numbers must be identical on both ends of a link for OSPF to form a full adjacency.

CCNA IP Routing Practice Question

This 200-301 practice question tests your understanding of ip routing. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

Network Topology
G0/010.0.12.1/30G0/110.0.23.2/30G0/110.0.23.2/30G0/010.0.13.2/30G0/010.0.13.2/30G0/110.0.13.1/30R1R2 (G0/0 10.0.12.2/30)R3 (G0/1 10.0.23.2/30)

You are connected to R1 via the console. Configure single-area OSPFv2 on R1, R2, and R3 so that all three routers can exchange routes. The current configuration has mismatched hello/dead timers on the link between R1 and R2, and an area mismatch on the link between R2 and R3. Correct these issues and ensure OSPF adjacencies form.

Question 1hardTroubleshooting
Review the full OSPF breakdown →

Exhibit

R1#show running-config | section router ospf
router ospf 1
 router-id 1.1.1.1
 network 10.0.12.0 0.0.0.3 area 0
 network 10.0.13.0 0.0.0.3 area 0
!
R1#show ip ospf interface gigabitethernet0/0
GigabitEthernet0/0 is up, line protocol is up
  Internet Address 10.0.12.1/30, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State DR, Priority 1
  Designated Router (ID) 1.1.1.1, Interface address 10.0.12.1
  Backup Designated router (ID) 2.2.2.2, Interface address 10.0.12.2
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
  No Hellos (Passive interface)
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2  (Backup Designated Router)
  Suppress hello for 0 neighbor(s)

R1#show ip ospf interface gigabitethernet0/1
GigabitEthernet0/1 is up, line protocol is up
  Internet Address 10.0.13.1/30, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State DR, Priority 1
  Designated Router (ID) 1.1.1.1, Interface address 10.0.13.1
  Backup Designated router (ID) 3.3.3.3, Interface address 10.0.13.2
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
  No Hellos (Passive interface)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 3.3.3.3  (Backup Designated Router)
  Suppress hello for 0 neighbor(s)

R2#show running-config | section router ospf
router ospf 1
 router-id 2.2.2.2
 network 10.0.12.0 0.0.0.3 area 0
 network 10.0.23.0 0.0.0.3 area 1
!
R2#show ip ospf interface gigabitethernet0/0
GigabitEthernet0/0 is up, line protocol is up
  Internet Address 10.0.12.2/30, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State BDR, Priority 1
  Designated Router (ID) 1.1.1.1, Interface address 10.0.12.1
  Backup Designated router (ID) 2.2.2.2, Interface address 10.0.12.2
  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

R2#show ip ospf interface gigabitethernet0/1
GigabitEthernet0/1 is up, line protocol is up
  Internet Address 10.0.23.2/30, Area 1
  Process ID 1, Router ID 2.2.2.2, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State DR, Priority 1
  Designated Router (ID) 2.2.2.2, Interface address 10.0.23.2
  Backup Designated router (ID) 0.0.0.0, Interface address 0.0.0.0
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

R3#show running-config | section router ospf
router ospf 1
 router-id 3.3.3.3
 network 10.0.13.0 0.0.0.3 area 0
 network 10.0.23.0 0.0.0.3 area 0
!
R3#show ip ospf interface gigabitethernet0/0
GigabitEthernet0/0 is up, line protocol is up
  Internet Address 10.0.13.2/30, Area 0
  Process ID 1, Router ID 3.3.3.3, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State BDR, Priority 1
  Designated Router (ID) 1.1.1.1, Interface address 10.0.13.1
  Backup Designated router (ID) 3.3.3.3, Interface address 10.0.13.2
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 1.1.1.1  (Designated Router)
  Suppress hello for 0 neighbor(s)

R3#show ip ospf interface gigabitethernet0/1
GigabitEthernet0/1 is up, line protocol is up
  Internet Address 10.0.23.2/30, Area 0
  Process ID 1, Router ID 3.3.3.3, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State DR, Priority 1
  Designated Router (ID) 3.3.3.3, Interface address 10.0.23.2
  Backup Designated router (ID) 0.0.0.0, Interface address 0.0.0.0
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

On R2, configure interface G0/0 with 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40', and modify the OSPF network statement for 10.0.23.0/30 to area 0.

The adjacency between R1 and R2 fails because R1 has hello/dead timers of 10/40, while R2 has 30/120 on G0/0. The adjacency between R2 and R3 fails because R2's G0/1 is in area 1, but R3's G0/1 is in area 0. On R2, change the hello/dead timers on G0/0 to match R1 (10/40) using 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40'. Also change the network statement for 10.0.23.0/30 to area 0 using 'network 10.0.23.0 0.0.0.3 area 0'. Verify with 'show ip ospf neighbor' on all routers.

Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • ✓

    On R2, configure interface G0/0 with 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40', and modify the OSPF network statement for 10.0.23.0/30 to area 0.

    Why this is correct

    This is correct because it fixes both issues: the hello/dead timers on R2's G0/0 are set to match R1's timers (10/40), and the network statement for the link between R2 and R3 is changed to area 0, resolving the area mismatch. After these changes, OSPF adjacencies will form on both links.

    Related concept

    OSPF neighbours must agree on key parameters.

  • ✗

    On R2, configure interface G0/0 with 'ip ospf hello-interval 30' and 'ip ospf dead-interval 120', and modify the OSPF network statement for 10.0.23.0/30 to area 1.

    Why it's wrong here

    This is incorrect because it changes the timers on R2 to match R2's current timers (30/120) instead of R1's (10/40), which would not resolve the mismatch. Additionally, changing the network statement to area 1 would keep the area mismatch with R3, which is in area 0.

  • ✗

    On R1, configure interface G0/0 with 'ip ospf hello-interval 30' and 'ip ospf dead-interval 120', and on R3, change the OSPF network statement for 10.0.23.0/30 to area 1.

    Why it's wrong here

    This is incorrect because it changes R1's timers to match R2's (30/120) instead of the other way around, and changes R3's area to area 1, which would still leave the area mismatch if R2 remains in area 1. The correct approach is to adjust R2 to match R1's timers and change R2's area to area 0.

  • ✗

    On R1, configure interface G0/0 with 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40', and on R2, modify the OSPF network statement for 10.0.23.0/30 to area 1.

    Why it's wrong here

    This is incorrect because R1 already has timers of 10/40, so reconfiguring them is unnecessary and does not fix the mismatch. Changing the network statement on R2 to area 1 would keep the area mismatch with R3, which is in area 0.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.

✓On R2, configure interface G0/0 with 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40', and modify the OSPF network statement for 10.0.23.0/30 to area 0.Correct answer▾

Why this is correct

This is correct because it fixes both issues: the hello/dead timers on R2's G0/0 are set to match R1's timers (10/40), and the network statement for the link between R2 and R3 is changed to area 0, resolving the area mismatch. After these changes, OSPF adjacencies will form on both links.

✗On R2, configure interface G0/0 with 'ip ospf hello-interval 30' and 'ip ospf dead-interval 120', and modify the OSPF network statement for 10.0.23.0/30 to area 1.Wrong answer — click to see why▾

Why this is wrong here

The specific factual error is that the timers should be made consistent by adjusting R2 to match R1, not the other way around, and the area mismatch requires both routers to be in the same area, which is area 0.

Why candidates choose this

Candidates might think that changing timers on R2 to match its own current values is correct, or that the area should be changed to area 1 to match R2's current configuration, but this would not fix the adjacency with R3.

✗On R1, configure interface G0/0 with 'ip ospf hello-interval 30' and 'ip ospf dead-interval 120', and on R3, change the OSPF network statement for 10.0.23.0/30 to area 1.Wrong answer — click to see why▾

Why this is wrong here

The specific factual error is that the timers can be adjusted on either router, but the area mismatch must be resolved by making both routers use the same area. Changing R3 to area 1 would not fix the adjacency if R2 is already in area 1? Actually, R2 is in area 1 on G0/1, so changing R3 to area 1 would make them match, but the question states the area mismatch is on the link between R2 and R3, and the existing explanation says to change R2's network statement to area 0. This option changes R3 instead, which could also work, but the question expects the correction on R2 as per the existing explanation. Additionally, changing R1's timers is not the most efficient if R1 is already configured correctly.

Why candidates choose this

Candidates might think that adjusting the router with the 'wrong' timers (R1) is necessary, or that changing the area on R3 is a valid alternative, but the existing explanation specifies the correction on R2.

✗On R1, configure interface G0/0 with 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40', and on R2, modify the OSPF network statement for 10.0.23.0/30 to area 1.Wrong answer — click to see why▾

Why this is wrong here

The specific factual error is that the timers on R1 are already correct, and the area mismatch requires both routers to be in the same area. Changing R2's area to area 1 would not match R3's area 0.

Why candidates choose this

Candidates might think that reconfiguring R1's timers is needed to 'ensure' they are correct, or that changing the area to area 1 on R2 is a valid fix, but it does not resolve the mismatch.

Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

Common exam traps

Common exam trap: OSPF can fail even when IP connectivity looks correct

OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.

Detailed technical explanation

How to think about this question

OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.

KKey Concepts to Remember

  • OSPF neighbours must agree on key parameters.
  • Router ID selection can affect neighbour relationships and LSDB output.
  • OSPF cost influences the preferred path.
  • A route can appear in OSPF information but not become the installed route.

TExam Day Tips

  • Check area mismatch first when OSPF adjacency fails.
  • Review passive interfaces when a network is advertised but no neighbour forms.
  • Use show ip ospf neighbor and show ip route clues carefully.

Key takeaway

OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.

Real-world example

How this comes up in practice

A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.

What to study next

Got this wrong? Here's your next step.

Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 200-301 OSPF questions on adjacency and route selection.

Related practice questions

Related 200-301 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Network Infrastructure and Connectivity practice questions

Practise 200-301 questions linked to Network Infrastructure and Connectivity.

Switching and Network Access practice questions

Practise 200-301 questions linked to Switching and Network Access.

IP Routing practice questions

Practise 200-301 questions linked to IP Routing.

Network Services and Security practice questions

Practise 200-301 questions linked to Network Services and Security.

AI and Network Operations practice questions

Practise 200-301 questions linked to AI and Network Operations.

CCNA subnetting practice questions

Practise IPv4 subnetting, CIDR, masks, host ranges and subnet selection.

CCNA OSPF practice questions

Practise OSPF neighbours, router IDs, metrics, areas and routing-table interpretation.

CCNA VLAN practice questions

Practise VLANs, access ports, trunks, allowed VLANs and switching scenarios.

CCNA STP practice questions

Practise spanning tree, root bridge election, port roles and STP troubleshooting.

CCNA EtherChannel practice questions

Practise LACP, PAgP, port-channel behaviour and bundle requirements.

CCNA ACL practice questions

Practise standard and extended ACLs, permit/deny logic and traffic filtering.

CCNA NAT practice questions

Practise static NAT, dynamic NAT, PAT and inside/outside address translation.

Practice this exam

Start a free 200-301 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions20 questions30 questions50 questionsTimed 30
200-301 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this 200-301 question test?

IP Routing — This question tests IP Routing — OSPF neighbours must agree on key parameters..

What is the correct answer to this question?

The correct answer is: On R2, configure interface G0/0 with 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40', and modify the OSPF network statement for 10.0.23.0/30 to area 0. — The adjacency between R1 and R2 fails because R1 has hello/dead timers of 10/40, while R2 has 30/120 on G0/0. The adjacency between R2 and R3 fails because R2's G0/1 is in area 1, but R3's G0/1 is in area 0. On R2, change the hello/dead timers on G0/0 to match R1 (10/40) using 'ip ospf hello-interval 10' and 'ip ospf dead-interval 40'. Also change the network statement for 10.0.23.0/30 to area 0 using 'network 10.0.23.0 0.0.0.3 area 0'. Verify with 'show ip ospf neighbor' on all routers.

What should I do if I get this 200-301 question wrong?

Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 200-301 OSPF questions on adjacency and route selection.

What is the key concept behind this question?

OSPF neighbours must agree on key parameters.

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

Same concept, more angles

2 more ways this is tested on 200-301

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. You are connected to R1 via the console. Configure OSPFv2 on R1 and R2 to establish a single-area OSPF adjacency in area 0. The link between R1 (G0/0) and R2 (G0/0) uses 10.0.0.0/30, and both routers must use an MTU of 1500. The current configuration has mismatched hello/dead timers and an area mismatch, preventing adjacency. Fix all issues so that R1 and R2 become fully adjacent.

hard
  • ✓ A.On R1, change the network statement to area 0 and set the hello interval to 5 under interface G0/0.
  • B.On R2, change the network statement to area 1 and set the hello interval to 10 under interface G0/0.
  • C.On R1, change the network statement to area 0 and set the MTU to 1500 under interface G0/0.
  • D.On R2, change the network statement to area 0 and set the dead interval to 40 under interface G0/0.

Why A: The adjacency fails because of two mismatches: the OSPF area on R1 is area 1 while R2 uses area 0, and the hello/dead timers differ (R1: 10/40, R2: 5/20). To fix, on R1 change the network statement to area 0 and adjust the hello interval to 5 (which also automatically sets dead to 20). Option B is wrong because it places the adjacency in area 1 (not area 0) and does not fix the timer mismatch on R2. Option C is wrong because it does not address the hello/dead timer mismatch; the MTU is already correct at 1500. Option D is wrong because it leaves the hello interval mismatched (10 vs 5) and alters the dead interval unnecessarily; the dead interval is automatically derived from the hello interval.

Variation 2. You are connected to R1. R1 has OSPF configured on GigabitEthernet0/0 with network 10.0.0.0 0.0.0.3 area 1, ip ospf hello-interval 10, and ip ospf dead-interval 40. R2 has OSPF configured on its GigabitEthernet0/0 with network 10.0.0.0 0.0.0.3 area 0, ip ospf hello-interval 5, and ip ospf dead-interval 20. Correct these mismatches so that R1 and R2 become OSPF neighbors.

hard
  • ✓ A.On R1, change the network statement to area 0 and set ip ospf hello-interval 5 and ip ospf dead-interval 20 under the interface.
  • B.On R2, change the network statement to area 1 and set ip ospf hello-interval 10 and ip ospf dead-interval 40 under the interface.
  • C.On R1, change the network statement to area 0 and set ip ospf hello-interval 10 and ip ospf dead-interval 40 under the interface.
  • D.On R2, change the network statement to area 0 and set ip ospf hello-interval 10 and ip ospf dead-interval 40 under the interface.

Why A: The OSPF adjacency fails due to two mismatches. First, the area is mismatched: R1 uses area 1, R2 uses area 0 (both must be the same area, typically area 0). Second, the hello and dead timers are mismatched: R1 uses Hello 10/Dead 40, R2 uses Hello 5/Dead 20. To fix, on R1 change the network statement to area 0 and adjust timers to match R2 (or vice versa). The solution below changes R1's area to 0 and sets hello to 5 and dead to 20 to match R2.

Last reviewed: Jun 6, 2026

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

Sign in to join the discussion.

This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.