- A
HA is configured in active/active mode, which does not support failover on link failure.
Why wrong: Active/active mode does support path monitoring; both firewalls handle traffic, but a link failure would affect only one.
- B
The passive firewall has lost its heartbeat connection to the active firewall.
Why wrong: If heartbeat were lost, both firewalls would consider themselves active or passive separately, but still the passive would not take over without path monitoring.
- C
The active firewall has a higher priority value.
Why wrong: Priority determines which firewall becomes active initially, but does not prevent failover when threshold conditions are met.
- D
Path monitoring is not configured on the interfaces.
Correct. Path monitoring monitors the status of data interfaces and triggers failover on link loss.
PCNSE Core Concepts and Architecture Practice Question
This PCNSE practice question tests your understanding of core concepts and architecture. 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 organization runs a pair of Palo Alto Networks firewalls in an active/passive HA configuration. During a maintenance window, the active firewall experiences a link down event on one of its data interfaces. The passive firewall does not assume the active role. What is the most likely reason?
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.
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
Path monitoring is not configured on the interfaces.
In an active/passive HA configuration, a link down event on a data interface does not automatically trigger a failover unless path monitoring is configured. Path monitoring allows the firewall to monitor the link state of specific data interfaces and initiate a failover when those interfaces go down. Without path monitoring, the passive firewall remains passive because it only monitors the HA heartbeat and the active firewall's health via the control link, not the data plane link state.
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.
- ✗
HA is configured in active/active mode, which does not support failover on link failure.
Why it's wrong here
Active/active mode does support path monitoring; both firewalls handle traffic, but a link failure would affect only one.
- ✗
The passive firewall has lost its heartbeat connection to the active firewall.
Why it's wrong here
If heartbeat were lost, both firewalls would consider themselves active or passive separately, but still the passive would not take over without path monitoring.
- ✗
The active firewall has a higher priority value.
Why it's wrong here
Priority determines which firewall becomes active initially, but does not prevent failover when threshold conditions are met.
- ✓
Path monitoring is not configured on the interfaces.
Why this is correct
Correct. Path monitoring monitors the status of data interfaces and triggers failover on link loss.
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
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume any link failure on a data interface will automatically trigger an HA failover, but Palo Alto Networks firewalls require explicit path monitoring configuration to initiate failover based on data plane link state.
Detailed technical explanation
How to think about this question
Path monitoring works by tracking the link state of selected data interfaces and comparing them against a configured threshold (e.g., number of failed interfaces). When the number of failed interfaces exceeds the threshold, the firewall triggers a failover by lowering its HA priority or sending a failover request. This is distinct from link monitoring, which only logs the event but does not cause a failover. In real-world scenarios, path monitoring is critical for ensuring that a firewall with a failed upstream switch port or fiber cut is replaced by its peer.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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.
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FAQ
Questions learners often ask
What does this PCNSE question test?
Core Concepts and Architecture — This question tests Core Concepts and Architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Path monitoring is not configured on the interfaces. — In an active/passive HA configuration, a link down event on a data interface does not automatically trigger a failover unless path monitoring is configured. Path monitoring allows the firewall to monitor the link state of specific data interfaces and initiate a failover when those interfaces go down. Without path monitoring, the passive firewall remains passive because it only monitors the HA heartbeat and the active firewall's health via the control link, not the data plane link state.
What should I do if I get this PCNSE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Last reviewed: Jun 25, 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.
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