PCNSE Deploy and Configure Firewalls Practice Question
A firewall receives traffic with IP options enabled. How does the firewall handle this traffic by default?
⚠ Common exam trap
Test-takers frequently assume the firewall forwards or strips IP options like a router, but Palo Alto Networks firewalls prioritize security by default and drop such packets to prevent IP option-based attacks.
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
✓
It drops the traffic
By default, Palo Alto Networks firewalls drop traffic with IP options enabled because IP options can be used to bypass security controls or evade inspection. The firewall treats such packets as a potential security risk and discards them to prevent IP option-based attacks, such as source routing or timestamp manipulation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
It drops the traffic
Why this is correct
By default, PAN-OS drops packets carrying IP options rather than forwarding them, since these options can be abused for reconnaissance or routing manipulation. This default behaviour satisfies the scenario's constraint of unconfigured handling, so the traffic is discarded before any policy evaluation.
- ✗
It forwards the traffic normally
Why it's wrong here
PAN-OS discards packets with IP options set rather than passing them through, since options such as source routing can subvert forwarding decisions. Normal forwarding is tempting because most traffic traverses the firewall untouched, but that applies to packets without options; the option bits themselves trigger the drop.
- ✗
It logs and alerts
Why it's wrong here
IP options are dropped by default under PAN-OS zone protection and threat settings, not merely logged; logging and alerting alone would still forward the packet. It is tempting because logging is a common response to suspicious packets, and administrators often enable alerts before enforcing a drop.
- ✗
It strips the IP options and forwards
Why it's wrong here
PAN-OS drops packets carrying IP options by default, so nothing is forwarded after stripping; the strip-and-forward behaviour belongs to a configured action, not the default. Stripping is tempting because some routers rewrite options in transit, but that is a routing function, not firewall handling.
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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.