Question 1hardmultiple choice
Full question →Question 284 of 1,000
Quick Answer
The answer is that the passive unit has a different firmware version. This is the most likely cause because FortiGate HA synchronization relies on identical data structures and feature sets between cluster members; when firmware versions differ, the passive unit cannot interpret or apply configuration and session data from the primary, resulting in an 'out of sync' status. On the Fortinet NSE 4 exam, this question tests your understanding of HA prerequisites—specifically that both units must run the exact same firmware image for sync to function, a detail often overlooked when troubleshooting failover events. A common trap is assuming network issues or link failures cause the sync status to drop, but the exam emphasizes firmware mismatch as the primary culprit. Remember the memory tip: “Same firmware, same sync—different version, out of sync.”
NSE4 System and Network Administration Practice Question
This NSE4 practice question tests your understanding of system and network administration. 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.
A FortiGate in HA active-passive cluster is experiencing failover events. The administrator runs 'get system ha status' and sees that the 'sync status' is 'out of sync'. 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.
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
✓
The passive unit has a different firmware version.
In an HA active-passive cluster, the 'sync status' indicates whether configuration and session data are synchronized between the primary and secondary units. When the passive unit has a different firmware version, the FortiGate cannot synchronize its configuration or sessions because the data structures and features may differ between versions, leading to an 'out of sync' status. This is a common prerequisite: both units must run the exact same firmware image for HA synchronization to function.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'session synchronization' with 'configuration synchronization' and assume that disabling session sync (Option B) would cause the 'sync status' to show 'out of sync', but the command output specifically reflects configuration sync status, not session sync.
Detailed technical explanation
How to think about this question
Under the hood, FortiGate HA uses a proprietary synchronization protocol over the heartbeat interface to replicate configuration changes (via 'config-sync') and session table entries (via 'session-sync'). The firmware version must match exactly because the binary format of configuration objects and session structures can change between releases; even a minor patch difference can cause serialization mismatches. In real-world scenarios, administrators often overlook firmware consistency during upgrades, leading to split-brain conditions or persistent 'out of sync' states that require manual intervention.
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 practitioner preparing for the NSE4 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this NSE4 question test?
System and Network Administration — This question tests System and Network Administration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The passive unit has a different firmware version. — In an HA active-passive cluster, the 'sync status' indicates whether configuration and session data are synchronized between the primary and secondary units. When the passive unit has a different firmware version, the FortiGate cannot synchronize its configuration or sessions because the data structures and features may differ between versions, leading to an 'out of sync' status. This is a common prerequisite: both units must run the exact same firmware image for HA synchronization to function.
What should I do if I get this NSE4 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.
About these practice questions
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Last reviewed: Jun 24, 2026
This NSE4 practice question is part of Courseiva's free Fortinet 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 NSE4 exam.
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