- A
Check the application override.
Why wrong: Application override affects application identification but not policy matching directly.
- B
Check the QoS policy.
Why wrong: QoS policy shapes traffic but does not deny it; a policy deny is from security rules.
- C
Check the rule order and ensure the allow rule is above any deny rules.
A rule order issue is the most common cause when a policy deny occurs despite an allow rule existing.
- D
Check the NAT policy for the traffic.
Why wrong: NAT policy does not cause a policy deny; it translates addresses but does not affect policy matching.
Question 317 of 516
PCNSE Troubleshoot Practice Question
This PCNSE practice question tests your understanding of troubleshoot. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
A network engineer notices that traffic from a specific subnet is being dropped by the firewall. The traffic log shows 'drop' with reason 'policy deny'. The engineer checks the security policy and confirms there is an allow rule for that subnet. What should be checked next?
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
✓
Check the rule order and ensure the allow rule is above any deny rules.
When a traffic log shows 'policy deny' despite an existing allow rule, the most common cause is rule order: Palo Alto firewalls evaluate security rules from top to bottom, and the first matching rule is applied. If a deny rule appears above the allow rule for the same subnet, the deny rule will match first and drop the traffic, making it essential to verify the rule sequence.
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.
- ✗
Check the application override.
Why it's wrong here
Application override affects application identification but not policy matching directly.
- ✗
Check the QoS policy.
Why it's wrong here
QoS policy shapes traffic but does not deny it; a policy deny is from security rules.
- ✓
Check the rule order and ensure the allow rule is above any deny rules.
Why this is correct
A rule order issue is the most common cause when a policy deny occurs despite an allow rule existing.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Check the NAT policy for the traffic.
Why it's wrong here
NAT policy does not cause a policy deny; it translates addresses but does not affect policy matching.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The common mistake is assuming that if an allow rule exists for the subnet, it will always be applied, ignoring that Palo Alto firewalls evaluate rules top-down and a higher-priority deny rule can preempt the allow rule.
Detailed technical explanation
How to think about this question
Palo Alto firewalls use a first-match model for security rules, meaning the rule with the lowest sequence number that matches the traffic is applied, and subsequent rules are ignored. The 'policy deny' log reason specifically indicates that a security rule (not an application, QoS, or NAT rule) denied the traffic, so the engineer must examine the rulebase order and look for any deny rules with broader source/destination or service matches that could preempt the intended allow rule. In complex environments, a common pitfall is a deny rule with a source zone of 'any' or a destination address that inadvertently covers the subnet in question.
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.
Visual reference
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PCNSE question test?
Troubleshoot — This question tests Troubleshoot — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Check the rule order and ensure the allow rule is above any deny rules. — When a traffic log shows 'policy deny' despite an existing allow rule, the most common cause is rule order: Palo Alto firewalls evaluate security rules from top to bottom, and the first matching rule is applied. If a deny rule appears above the allow rule for the same subnet, the deny rule will match first and drop the traffic, making it essential to verify the rule sequence.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 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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