PCNSE Secure Access and VPN Practice Question
An administrator configures a VPN tunnel between two Palo Alto firewalls. The tunnel shows as active, but traffic is not being encrypted. What configuration step is most likely missing?
⚠ Common exam trap
It's easy for candidates to assume an active VPN tunnel automatically encrypts all traffic routed to it, overlooking that Palo Alto firewalls enforce security policies as a prerequisite for any inter-zone traffic, including traffic destined for a tunnel interface.
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
✓
A security policy allowing traffic from the tunnel interface to the destination.
Even when a VPN tunnel is active (Phase 1 and Phase 2 SAs are established), traffic will not be encrypted unless a security policy explicitly permits traffic from the tunnel interface to the destination zone. On Palo Alto firewalls, inter-zone traffic requires a security policy to allow the session; without it, the firewall drops the traffic before it can be encrypted and sent over the tunnel. The tunnel being up only indicates IKE/IPsec negotiation succeeded, not that data-plane forwarding is authorized.
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 encryption algorithm must be set to null.
Why it's wrong here
Incorrect. Setting null encryption would disable encryption, not cause no encryption.
- ✗
A NAT policy to translate private addresses.
Why it's wrong here
Incorrect. NAT is not required for VPN; encryption can happen on private IPs.
- ✓
A security policy allowing traffic from the tunnel interface to the destination.
Why this is correct
Correct. Without a policy, traffic is dropped.
- ✗
The tunnel interface must be assigned to a security zone.
Why it's wrong here
Incorrect. Tunnel interfaces can be in the default zone; missing zone does not prevent encryption.
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.