NSE4 High Availability and Diagnostics Practice Question
An administrator is troubleshooting a FortiGate HA cluster that is experiencing frequent failovers. The heartbeat interfaces are configured on port1 and port2. Which diagnostic command should the administrator use to check heartbeat packet loss?
⚠ Common exam trap
NSE4 often tests the confusion between HA status commands ('get system ha status', 'diagnose sys ha status') and the heartbeat-specific diagnostic, so candidates pick a status command that shows roles but not packet loss.
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
✓
diagnose sys ha heartbeat
The 'diagnose sys ha heartbeat' command is the dedicated diagnostic tool for inspecting HA heartbeat interface statistics, including packet counts, errors, and loss on the configured heartbeat ports (port1 and port2 in this scenario). It shows per-interface heartbeat traffic details that directly reveal whether heartbeats are being dropped, which is the root cause of frequent failovers. This is the only option that targets heartbeat packet-level diagnostics rather than general HA state.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
diagnose sys ha status
Why it's wrong here
This diagnostic command displays the current HA cluster state, including each unit's role (primary or secondary), priority, and synchronization mode. It relies on information already computed by the HA state machine, so it cannot reveal real-time heartbeat link quality or packet loss counters. If you suspect a heartbeat fault, this command will show you the result of the fault (e.g., standby status) but not the cause, making it insufficient for packet-loss analysis.
- ✗
get system ha status
Why it's wrong here
This is a system-level 'get' command that presents the configured HA parameters, such as cluster mode, group name, and member serial numbers, along with the current role. It is useful for verifying that all FortiGates share the same HA configuration and can see each other, but it does not track heartbeat packets or measure loss. Unlike the heartbeat-specific command, it accesses the management configuration rather than kernel counters, so it cannot quantify packet loss on the heartbeat interface.
- ✓
diagnose sys ha heartbeat
Why this is correct
This command queries the HA daemon's internal statistics and specifically reports the number of consecutive sent and received heartbeat packets as well as the computed packet loss rate. It is the only command in this list that directly measures the reliability of the heartbeat link, which is essential for diagnosing intermittent failovers or a split-brain condition. A non-zero loss percentage here indicates a degraded heartbeat path, pointing to physical-layer issues such as bad cables, duplex mismatches, or congested interfaces.
- ✗
diagnose sys session list
Why it's wrong here
This command lists the NAT and session table entries for traffic passing through the FortiGate, showing source/destination IPs, ports, and protocols. It is meant for troubleshooting user traffic flows and policy behavior, not for HA cluster diagnostics. Heartbeat packets are sent through a dedicated multicast channel bypassing the session table, so this command will never display them and cannot reveal any heartbeat packet loss, making it irrelevant to this HA cluster problem.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Fortinet exam blueprint
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.