PCNSE Manage, Monitor and Operate Practice Question
Two firewalls in an active/passive HA pair are not synchronizing. The administrator checks 'show high-availability state' and sees 'active' on both firewalls. What is the most likely cause?
⚠ Common exam trap
Candidates often assume both firewalls showing 'active' is caused by a configuration mismatch like PAN-OS versions or preemptive settings, but the core issue is the loss of the HA3 control link, which prevents heartbeat detection and triggers a split-brain condition.
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 HA3 control link is misconfigured or down.
When both firewalls show 'active' in the HA state, it indicates a split-brain scenario where each firewall believes it is the active unit. The HA3 control link is responsible for heartbeat and state synchronization; if it is misconfigured or down, the firewalls cannot detect each other's presence, causing both to assume active status. This is the most common cause of dual-active HA failures.
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 HA3 control link is misconfigured or down.
Why this is correct
Without heartbeat, each firewall assumes the other is down and becomes active.
- ✗
Session owner is set to 'primary' on both firewalls.
Why it's wrong here
Session owner is for flow control, not HA state.
- ✗
Preemptive mode is enabled on both firewalls.
Why it's wrong here
Preemptive mode only affects failback behavior, not the initial state.
- ✗
Both firewalls have different PAN-OS versions.
Why it's wrong here
Version mismatch would prevent configuration sync, but both would still show as standbys or one active.
Go deeper
Related to this question
About these practice questions
This PCNSE question is part of Courseiva's 504-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCNSE practice question is part of Courseiva's free Palo Alto Networks 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 PCNSE exam.