The answer is an unstable OSPF neighbor relationship causing intermittent route flapping. When an OSPF adjacency repeatedly goes up and down, the router continuously adds and removes the learned route for 10.2.2.0/24 from the routing table, leading to inconsistent reachability—the ping works when the route is present and fails when it disappears. This scenario tests your understanding of OSPF route flapping causes, a common troubleshooting topic on the Systems Security Certified Practitioner SSCP exam, where you must differentiate between static route misconfiguration and dynamic protocol instability. A frequent trap is assuming a static route is always preferred, but OSPF’s administrative distance can override it when the neighbor is stable; here, the flapping itself is the root issue. Memory tip: “Flapping flaps the table” – if reachability toggles, suspect the neighbor relationship, not the static entry.
SSCP Network and Communications Security Practice Question
This SSCP practice question tests your understanding of network and communications security. 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.
Exhibit
Refer to the exhibit.
Router# show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is 10.1.1.2 to network 0.0.0.0
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/0
O 10.2.2.0/24 [110/20] via 10.1.1.2, 00:05:12, GigabitEthernet0/0
S 10.3.3.0/24 [1/0] via 10.1.1.2
C 192.168.1.0/24 is directly connected, GigabitEthernet0/1
A network administrator is unable to ping the server at 10.2.2.100 from a host on the 192.168.1.0/24 network. Based on the exhibit, what is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
Router# show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is 10.1.1.2 to network 0.0.0.0
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
C 10.1.1.0/24 is directly connected, GigabitEthernet0/0
O 10.2.2.0/24 [110/20] via 10.1.1.2, 00:05:12, GigabitEthernet0/0
S 10.3.3.0/24 [1/0] via 10.1.1.2
C 192.168.1.0/24 is directly connected, GigabitEthernet0/1
A
The static route to 10.3.3.0 is misconfigured.
Why wrong: The static route is present and not affecting 10.2.2.0.
B
The gateway of last resort is missing.
Why wrong: The default route is configured as 10.1.1.2.
C
The OSPF route for 10.2.2.0 is not in the routing table.
Why wrong: It is present as an OSPF route.
D
The OSPF neighbor relationship may be unstable, causing intermittent route flapping.
The route is learned but the age (00:05:12) may indicate recent instability.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The OSPF neighbor relationship may be unstable, causing intermittent route flapping.
The exhibit shows that the host on 192.168.1.0/24 cannot reach 10.2.2.100, but the routing table includes both a static route to 10.3.3.0 and an OSPF route to 10.2.2.0. Option D is correct because the symptom of intermittent reachability (sometimes ping works, sometimes not) combined with a known OSPF neighbor relationship points to route flapping, where the OSPF route for 10.2.2.0 is repeatedly added and removed due to an unstable neighbor adjacency, causing the ping to fail when the route is absent.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The static route to 10.3.3.0 is misconfigured.
Why it's wrong here
The static route is present and not affecting 10.2.2.0.
The OSPF neighbor relationship may be unstable, causing intermittent route flapping.
Why this is correct
The route is learned but the age (00:05:12) may indicate recent instability.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between a missing route (which would cause a complete failure) and an unstable route (which causes intermittent failure), tricking candidates into choosing a static answer like 'missing route' when the symptom of intermittent connectivity points to route flapping.
Detailed technical explanation
How to think about this question
OSPF uses Hello packets to maintain neighbor adjacencies; if the link is flapping (e.g., due to a faulty cable, duplex mismatch, or high error rates), the neighbor state may bounce between Full and Down, causing the route to be withdrawn and re-advertised repeatedly. This route flapping can be observed with 'show ip ospf neighbor' and 'debug ip ospf adj', and it leads to intermittent connectivity as the routing table updates, which matches the scenario where the ping sometimes fails and sometimes succeeds.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network and Communications Security — This question tests Network and Communications Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The OSPF neighbor relationship may be unstable, causing intermittent route flapping. — The exhibit shows that the host on 192.168.1.0/24 cannot reach 10.2.2.100, but the routing table includes both a static route to 10.3.3.0 and an OSPF route to 10.2.2.0. Option D is correct because the symptom of intermittent reachability (sometimes ping works, sometimes not) combined with a known OSPF neighbor relationship points to route flapping, where the OSPF route for 10.2.2.0 is repeatedly added and removed due to an unstable neighbor adjacency, causing the ping to fail when the route is absent.
What should I do if I get this SSCP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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