PCNSE Troubleshoot Practice Question
A security administrator reports that they can ping and access internal resources, but cannot access any external websites. The firewall is configured with a default route pointing to the internet router, and the NAT policy includes a source NAT rule for the internal subnet. Which step should the administrator take first to troubleshoot this issue?
⚠ Common exam trap
The trap here is that candidates often jump to checking NAT or routing first because those are common misconfigurations, but the PCNSE exam emphasizes that security policy is the first gatekeeper in the firewall's processing order, and without an allow rule, no traffic passes regardless of NAT or route correctness.
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
✓
Review the security policy to ensure traffic from the internal zone to the external zone is allowed.
The administrator can ping and access internal resources but cannot reach external websites, which indicates that basic IP connectivity and internal routing are functional. Since the firewall has a default route and a source NAT rule configured, the most likely cause is that a security policy is blocking traffic from the internal zone to the external zone. In Palo Alto Networks firewalls, security policies are evaluated before NAT, so even with correct NAT and routing, traffic will be dropped if no allow rule exists for the session.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Check the NAT rule for correct interface assignment.
Why it's wrong here
The NAT rule is already configured and internal access works, so NAT is likely functioning.
- ✗
Check the DNS proxy configuration on the firewall.
Why it's wrong here
DNS proxy would affect name resolution, but the issue could persist even with DNS if the web traffic is blocked by policy.
- ✓
Review the security policy to ensure traffic from the internal zone to the external zone is allowed.
Why this is correct
If internal access works but external website access fails, the most likely cause is a security policy blocking web traffic. Checking the security policy is the logical first step.
- ✗
Verify that the default route is active by checking the routing table.
Why it's wrong here
Internal access working indicates routing is likely correct.
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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.