PCNSA Policy Evaluation and Management Practice Question
A network administrator adds a new security rule allowing HTTP from the Trust zone to the Untrust zone. After committing, traffic from the Trust zone to the Untrust zone is still blocked. What is the most likely cause?
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 new rule is placed at the bottom of the policy, below an existing deny rule that matches the same traffic.
The most likely cause is that the new rule is placed at the bottom of the security policy rulebase. Palo Alto Networks firewalls evaluate rules from top to bottom. If an existing deny rule that matches the same traffic (e.g., any-any deny) is placed above the new allow rule, the deny rule will match first and block the traffic. Therefore, the new allow rule never gets evaluated. Option C correctly identifies this issue.
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 source zone in the new rule is set to 'Untrust' instead of 'Trust'.
Why it's wrong here
Incorrect. If the source zone were wrong, the rule would not match at all, but the symptom is the traffic is blocked, not unmatched.
- ✗
The application in the new rule is set to 'ssl' instead of 'http'.
Why it's wrong here
Incorrect. If the application mismatches, the rule would not apply, but the traffic would still be subject to other rules. The most likely cause is rule order.
- ✓
The new rule is placed at the bottom of the policy, below an existing deny rule that matches the same traffic.
Why this is correct
Correct. Policy evaluation is top-down, so a deny rule above the allow rule will block traffic.
- ✗
The destination zone in the new rule is set to 'Trust' instead of 'Untrust'.
Why it's wrong here
Incorrect. Similar to option B, a zone mismatch would result in no match, not a block.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCNSA 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 PCNSA exam.