The answer is that session synchronization is configured to maintain stateful failover. This is correct because in an active-passive HA cluster, only the active unit processes and forwards traffic while the passive unit remains in standby, so replicating session tables from the active to the passive unit ensures that when a failover occurs, established connections are seamlessly preserved without interruption. On the Fortinet NSE 4 Network Security Professional exam, this concept tests your understanding of how FortiGate HA achieves high availability without load sharing, and a common trap is confusing active-passive with active-active, where both units forward traffic. Remember the memory tip: “Passive waits, active creates; sync the sessions to seal the fates.”
NSE4 System and Network Administration Practice Question
This NSE4 practice question tests your understanding of system and network administration. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 is configuring a FortiGate HA cluster in active-passive mode. Which two statements are correct about this configuration?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
One unit is active and forwards traffic, while the other is passive and does not forward traffic unless a failover occurs.
In an active-passive HA cluster, only the active unit processes and forwards traffic, while the passive unit remains in standby mode and does not forward traffic unless a failover occurs. This ensures high availability without load sharing. Additionally, session synchronization is configured to replicate stateful session information from the active to the passive unit, enabling seamless failover without disrupting established sessions.
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 cluster IP address is assigned to both units simultaneously.
Why it's wrong here
The cluster IP is only on the active unit.
✓
One unit is active and forwards traffic, while the other is passive and does not forward traffic unless a failover occurs.
Why this is correct
This defines active-passive HA.
Related concept
Read the scenario before looking for a memorised answer.
✗
Both units can forward traffic simultaneously.
Why it's wrong here
That describes active-active HA.
✗
Heartbeat interfaces are optional.
Why it's wrong here
Heartbeat is required for HA.
✓
Session synchronization is configured to maintain stateful failover.
Why this is correct
Session sync is critical for seamless failover.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse active-passive with active-active mode, mistakenly thinking both units can forward traffic simultaneously, or they assume the cluster IP is shared by both units at all times.
Detailed technical explanation
How to think about this question
FortiGate HA uses a dedicated heartbeat link (typically a physical interface or VLAN) to exchange keepalive messages and session synchronization data using FGCP (FortiGate Cluster Protocol). The passive unit maintains a synchronized copy of the session table via FGCP, and upon failover, it takes over the cluster IP and MAC address to continue forwarding traffic with minimal interruption. In real-world deployments, a dedicated heartbeat interface is critical to avoid split-brain scenarios and ensure reliable failover detection.
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.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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: One unit is active and forwards traffic, while the other is passive and does not forward traffic unless a failover occurs. — In an active-passive HA cluster, only the active unit processes and forwards traffic, while the passive unit remains in standby mode and does not forward traffic unless a failover occurs. This ensures high availability without load sharing. Additionally, session synchronization is configured to replicate stateful session information from the active to the passive unit, enabling seamless failover without disrupting established sessions.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
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. An administrator is configuring a FortiGate HA cluster in active-passive mode with two units. Which three conditions must be met for failover to occur? (Choose three.)
hard
✓ A.A monitored interface on the primary unit goes down
✓ B.The primary unit loses all heartbeat communication with the secondary unit
C.The secondary unit receives a higher priority configuration
D.The primary unit's CPU usage exceeds 90%
✓ E.The primary unit stops sending session synchronization packets
Why A: Option A is correct because in an active-passive HA cluster, a monitored interface going down on the primary unit triggers a failover. The FortiGate HA daemon detects the link failure and, if the interface is configured as a monitored interface, the primary unit will relinquish its active role, allowing the secondary unit to take over.
Last reviewed: Jun 24, 2026
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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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