- A
The security policy on Site B does not include the user subnet as a source VPN zone traffic
The policy must have the correct source zone (trust) and destination zone (VPN) and include the user subnet.
- B
NAT is translating the user's IP to an incorrect address
Why wrong: NAT would affect the firewall's own ping as well.
- C
The IPsec tunnel has a misconfigured proxy ID
Why wrong: Proxy ID mismatch would prevent phase 2, but the tunnel is established.
- D
The Site A firewall has a route missing for the Site B user subnet
Why wrong: The firewall can reach the server, so routing is fine.
Question 346 of 516
PCNSE Secure Access and VPN Practice Question
This PCNSE practice question tests your understanding of secure access and vpn. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
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?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 correct answer is A because 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.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
NAT is translating the user's IP to an incorrect address
- ✗
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates 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.
Detailed technical explanation
How to think about this question
In policy-based IPsec VPNs, traffic is matched by proxy IDs (local and remote subnets) to determine which packets are encrypted. However, the security policy on the firewall still governs whether traffic is allowed to enter the VPN tunnel. The firewall's own ping uses its egress interface IP as the source, which is often in a different zone (e.g., self or trust) and may be permitted by a separate rule, while user traffic from a specific subnet requires an explicit source match in the policy. This is a common misconfiguration where the tunnel is up but the security rule lacks the correct source zone or address.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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.
What to study next
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FAQ
Questions learners often ask
What does this PCNSE question test?
Secure Access and VPN — This question tests Secure Access and VPN — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The security policy on Site B does not include the user subnet as a source VPN zone traffic — The correct answer is A because 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.
What should I do if I get this PCNSE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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.
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