PCNSE Troubleshoot Practice Question
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?
⚠ Common exam trap
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.
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.
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.
- ✗
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.
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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.