hardMultiple ChoiceObjective-mapped
PCNSA Practice Question: Is experiencing high CPU utilization on the…
An organization is experiencing high CPU utilization on the firewall dataplane, causing latency in packet processing. The administrator notices that a large number of small packets are being processed by a specific security rule that allows any service. What is the best first step to reduce CPU load without impacting legitimate traffic?
⚠ Common exam trap
Test-takers frequently confuse QoS with DoS protection, thinking that rate-limiting or blocking is the same as shaping, but QoS is designed to manage bandwidth without dropping traffic, whereas DoS protection thresholds can inadvertently drop legitimate traffic if not carefully tuned.
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
✓
Create a QoS policy to limit bandwidth for that traffic class
Applying a QoS policy to limit bandwidth for the traffic class causing high CPU utilization will throttle the rate at which small packets are processed, reducing the dataplane load without dropping legitimate traffic. QoS allows the firewall to prioritize or rate-limit specific traffic classes, which directly addresses the high volume of small packets without altering security rules or session behavior.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Remove the rule and create a more specific rule with a narrower service
Why it's wrong here
Removing the rule would block all traffic matching the original rule, impacting operations.
- ✗
Apply a DoS protection profile with a session rate threshold
Why it's wrong here
DoS protection can help but may drop legitimate bursts; QoS is a more direct approach to manage bandwidth.
- ✓
Create a QoS policy to limit bandwidth for that traffic class
Why this is correct
QoS can throttle the amount of traffic processed, reducing CPU utilization while still allowing legitimate traffic.
- ✗
Increase the session timeout to avoid creating new sessions
Why it's wrong here
Increasing session timeout does not reduce the number of packets being inspected; it only keeps sessions open longer.
Go deeper
Related to this question
About these practice questions
One of 516 original PCNSA practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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.