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.
An administrator configures a FortiGate HA cluster with two units in active-passive mode. After setup, the secondary unit shows 'standby' status but traffic is not failing over when the primary is shut down. 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.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 primary unit's configuration changes were not synchronized to the secondary.
Option D is correct because in an active-passive HA cluster, the secondary unit must have a synchronized copy of the primary's configuration to take over traffic. If configuration synchronization is not enabled or fails, the secondary remains in standby but lacks the necessary policies and settings to handle traffic, so failover does not occur even though HA status appears normal.
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 assume 'standby' status guarantees failover readiness, but FortiGate requires configuration synchronization to be explicitly enabled and successful for the standby unit to take over traffic; otherwise, it remains a passive observer without operational policies.
Detailed technical explanation
How to think about this question
FortiGate HA uses heartbeat interfaces (typically dedicated or VLAN interfaces) to exchange keepalive messages and synchronize configurations via the HA synchronization mechanism (config-sync). If config-sync is disabled or the secondary unit fails to receive the full configuration (e.g., due to network issues or mismatched firmware), the secondary remains in standby but cannot process traffic because it lacks the necessary firewall policies, routes, and objects. In real-world scenarios, administrators often overlook the 'config-sync' setting under 'config system ha' or forget to enable 'set sync-config enable', leading to this exact failure mode.
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 network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
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 primary unit's configuration changes were not synchronized to the secondary. — Option D is correct because in an active-passive HA cluster, the secondary unit must have a synchronized copy of the primary's configuration to take over traffic. If configuration synchronization is not enabled or fails, the secondary remains in standby but lacks the necessary policies and settings to handle traffic, so failover does not occur even though HA status appears normal.
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", "primary". 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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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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