PCNSE Secure Access and VPN Practice Question
Which TWO of the following are supported authentication methods for IPSec VPN tunnel setup between two Palo Alto Networks firewalls?
⚠ Common exam trap
Test-takers frequently confuse user authentication methods (RADIUS, SAML, LDAP) with device-to-device IPsec tunnel authentication, which only supports pre-shared keys and certificates on Palo Alto firewalls.
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
✓
Certificate
Palo Alto Networks firewalls support certificate-based authentication for IKEv1 and IKEv2 IPsec VPN tunnels, where each peer presents an X.509 certificate signed by a trusted CA. This method provides strong mutual authentication and is commonly used in large-scale or high-security deployments.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Certificate
Why this is correct
Certificate authentication is supported for IPSec tunnels.
- ✗
RADIUS
Why it's wrong here
RADIUS is used for user authentication, not for IPSec peer authentication.
- ✗
SAML
Why it's wrong here
SAML is used for web-based authentication, not IPSec.
- ✗
LDAP
Why it's wrong here
LDAP is used for user authentication, not IPSec.
- ✓
Pre-shared key
Why this is correct
PSK is a standard IPSec authentication method.
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.