PCNSE Secure Access and VPN Practice Question
A small company has two sites connected by a policy-based IPsec VPN. Users at Site B report they cannot reach a server at Site A with IP 10.1.1.100. The firewall administrator checks the VPN monitor and sees the tunnel is active and IKE SAs are up. From the Site B firewall, a ping to 10.1.1.100 succeeds. However, a user on a PC (192.168.50.10) behind the Site B firewall cannot ping 10.1.1.100. The security policy on the Site B firewall allows traffic from trust to VPN zones. What is the most likely cause of the issue?
⚠ Common exam trap
Many exam-takers assume a working tunnel and successful ping from the firewall guarantee user traffic will work, overlooking that security policies apply per source zone and address, and the firewall's own traffic is handled differently from user traffic.
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 security policy on Site B does not include the user subnet as a source VPN zone traffic
The security policy on Site B must explicitly include the user subnet (192.168.50.0/24) as a source in the rule that permits traffic to the VPN zone. Even though the tunnel is up and the firewall itself can reach 10.1.1.100 (bypassing policy checks), user traffic is subject to security rules. Without the user subnet as a source, the policy drops the traffic, causing the connectivity failure.
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 security policy on Site B does not include the user subnet as a source VPN zone traffic
Why this is correct
The policy must have the correct source zone (trust) and destination zone (VPN) and include the user subnet.
- ✗
NAT is translating the user's IP to an incorrect address
Why it's wrong here
NAT would affect the firewall's own ping as well.
- ✗
The IPsec tunnel has a misconfigured proxy ID
Why it's wrong here
Proxy ID mismatch would prevent phase 2, but the tunnel is established.
- ✗
The Site A firewall has a route missing for the Site B user subnet
Why it's wrong here
The firewall can reach the server, so routing is fine.
Visual reference
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
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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.