PCNSA Policy Evaluation and Management Practice Question
A firewall administrator notices that a security rule intended to block traffic from a specific IP address is not working. The rule is placed at the bottom of the security rulebase, and the traffic is being allowed by a rule higher in the list. What is the most likely cause?
⚠ Common exam trap
A common mix-up: candidates think rule order does not matter or that a block rule can override an allow rule regardless of position, but Palo Alto Networks enforces strict top-down evaluation where the first match wins, so a lower rule cannot override a higher rule's action.
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 rule is positioned below an allow rule that matches the same traffic.
The Palo Alto Networks firewall evaluates security rules in top-down order, from the first rule in the rulebase to the last. If a rule that allows traffic is placed higher in the list, it will match and permit the traffic before the lower-placed block rule is ever evaluated. The block rule at the bottom is effectively never reached for that traffic, which is why the intended blocking action fails.
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 IP is negated in the rule.
Why it's wrong here
Negate source would exclude that IP, but the rule is meant to block it; not mentioned.
- ✗
The rule is placed at the top of the rulebase and overridden by a later rule.
Why it's wrong here
If at the top, it would match first; but it is at the bottom.
- ✓
The rule is positioned below an allow rule that matches the same traffic.
Why this is correct
First match wins, so the allow rule matches before the block rule.
- ✗
The rule is disabled in the rulebase.
Why it's wrong here
There is no indication the rule is disabled; it is simply not reached.
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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.