NSE7 Enterprise Firewall and VDOMs Practice Question
An administrator has configured a FortiGate HA cluster with two units. The cluster uses a virtual cluster for load balancing in active-active mode. The administrator notices that traffic from one VDOM is not being load-balanced and is only handled by one unit. What is the most likely cause?
⚠ Common exam trap
Test-takers frequently assume active-active mode automatically load-balances all traffic across both units, overlooking the requirement that each VDOM must be explicitly assigned to a virtual cluster to enable load balancing for that VDOM.
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 VDOM is not assigned to any virtual cluster
In an active-active HA cluster with virtual clusters, each VDOM must be explicitly assigned to a virtual cluster to participate in load balancing. If a VDOM is not assigned to any virtual cluster, it defaults to being handled only by the primary unit, regardless of the cluster mode. This explains why traffic from that VDOM is not load-balanced.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Session pickup is disabled
Why it's wrong here
Session pickup synchronises session state between cluster units for failover continuity; it does not govern which unit initially handles a new session. Disabling it is the correct choice when you want to reduce HA sync overhead and accept session loss on failover. Traffic distribution is controlled by virtual cluster and load-balance settings.
- ✗
The HA priority is set to 0 on the secondary unit
Why it's wrong here
HA priority determines which unit becomes primary during failover, not how active-active sessions are distributed. Setting priority to 0 is relevant when forcing a specific unit to stay secondary in an active-passive pair. Load balancing instead relies on virtual cluster configuration and session pickup behaviour.
- ✓
The VDOM is not assigned to any virtual cluster
Why this is correct
Virtual clustering distributes traffic across units only for VDOMs explicitly assigned to a virtual cluster. A VDOM left outside every virtual cluster has no load-balancing scope, so all its traffic is processed by the primary unit alone.
- ✗
The management interface is not configured on the VDOM
Why it's wrong here
Management interface configuration is unrelated to per-VDOM traffic distribution; it only affects administrative access. That setting matters when you need out-of-band management on a dedicated VDOM. Load balancing across HA units depends on session distribution settings and virtual cluster membership, not management access.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This NSE7 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 NSE7 exam.