PCNSE Deploy and Configure Firewalls Practice Question
An administrator adds a new security rule to allow outbound 'web-browsing' and 'ssl' traffic. After committing, users report that some HTTPS sites are still blocked. Traffic logs show that the traffic matches the new rule but is denied. What is the most likely cause?
⚠ Common exam trap
Many exam-takers assume 'application-default' allows any port for the application, when in reality it strictly enforces the default port, causing denial for HTTPS on non-standard ports.
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 service 'application-default' does not match the port used by the site.
When a security rule uses the 'application-default' service, the firewall only allows traffic that matches the default port for the specified application. For 'web-browsing' (HTTP), the default port is TCP 80, and for 'ssl' (HTTPS), the default port is TCP 443. If an HTTPS site uses a non-standard port (e.g., TCP 8443), the traffic matches the rule based on the application but is denied because the service 'application-default' does not recognize that port as valid for the application.
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 service 'application-default' does not match the port used by the site.
Why this is correct
Application-default restricts matching to the standard port for the application, so sites on non-standard ports do not match.
- ✗
A decryption policy is required for HTTPS traffic.
Why it's wrong here
Decryption is not required for the rule to allow traffic, but it may affect URL filtering; however, the traffic is being denied, not just filtered.
- ✗
The application filter does not include 'ssl'.
Why it's wrong here
The rule allows 'ssl', so the filter includes it.
- ✗
The rule is placed too low in the rulebase.
Why it's wrong here
If the traffic matches the rule, placement is not the issue.
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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.