This PCNSE practice question tests your understanding of managing troubleshooting and high availability. 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 notices that the HA pair shows a state mismatch: one firewall reports active, the other reports passive, but traffic is not flowing through the active firewall. 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.
Session synchronization is incomplete
Why wrong: Incomplete session sync does not cause state mismatch.
The HA2 link is down
Why wrong: HA2 link failure affects session sync, not state.
The passive firewall has a higher priority
Why wrong: Higher priority means it would become active, not cause mismatch.
The HA1 link is down and preemptive mode is enabled
With HA1 down and preemptive, both may attempt to become active, leading to mismatch.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The HA1 link is down and preemptive mode is enabled
Option B is correct because a HA1 link failure can cause both firewalls to think they are active (split-brain), but the state mismatch indicates one sees active, one sees passive; this is often due to a preemptive configuration or hold timer issue. Option A is wrong because HA2 link failure does not cause state mismatch; it only affects session sync.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Session synchronization is incomplete
Why it's wrong here
Incomplete session sync does not cause state mismatch.
The HA2 link is down
Why it's wrong here
HA2 link failure affects session sync, not state.
The passive firewall has a higher priority
Why it's wrong here
Higher priority means it would become active, not cause mismatch.
The HA1 link is down and preemptive mode is enabled
Why this is correct
With HA1 down and preemptive, both may attempt to become active, leading to mismatch.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the PCNSE 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
Identify which PCNSE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Managing Troubleshooting and High Availability — study guide chapter
Learn the concepts, then practise the questions
Managing Troubleshooting and High Availability practice questions
Targeted practice on this topic area only
All PCNSE questions
516 questions across all exam domains
Palo Alto Networks Certified Network Security Engineer PCNSE study guide
Full concept coverage aligned to exam objectives
PCNSE practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise PCNSE questions linked to Manage, Monitor and Operate.
Practise PCNSE questions linked to Securing Traffic and App-ID.
Practise PCNSE questions linked to Securing Users and Applications with Authentication.
Practise PCNSE questions linked to Decryption and SSL Inspection.
Practise PCNSE questions linked to Managing Troubleshooting and High Availability.
Practise PCNSE questions linked to Deploy and Configure Firewalls.
Practise PCNSE questions linked to Core Concepts and Architecture.
Practise PCNSE questions linked to Secure Access and VPN.
Practise PCNSE questions linked to Troubleshoot.
Practise PCNSE questions linked to PCNSE fundamentals.
Practise PCNSE questions linked to PCNSE scenario.
Practise PCNSE questions linked to PCNSE troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Managing Troubleshooting and High Availability — This question tests Managing Troubleshooting and High Availability — Read the scenario before looking for a memorised answer..
The correct answer is: The HA1 link is down and preemptive mode is enabled — Option B is correct because a HA1 link failure can cause both firewalls to think they are active (split-brain), but the state mismatch indicates one sees active, one sees passive; this is often due to a preemptive configuration or hold timer issue. Option A is wrong because HA2 link failure does not cause state mismatch; it only affects session sync.
Identify which PCNSE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Last reviewed: Jun 24, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.