PCNSA Decryption and Monitoring Practice Question
An organization uses inbound inspection decryption for their public-facing web servers. They have imported the server's certificate and private key into the firewall. However, some clients report 'untrusted certificate' warnings. What is the most likely cause?
⚠ Common exam trap
Palo Alto Networks often tests the distinction between importing the server certificate (for re-encryption) and importing the root CA certificate (for chain completeness), leading candidates to assume the server certificate alone is sufficient for trust.
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 firewall is not configured with the root CA certificate
When a firewall performs inbound inspection decryption, it re-encrypts traffic using the server's certificate. If the firewall does not have the root CA certificate that issued the server's certificate, the firewall cannot present a complete certificate chain to clients. Clients then see the certificate as untrusted because the issuing CA is not recognized, even though the server's certificate and private key are correctly imported.
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 server's certificate is using an unsupported cipher
Why it's wrong here
Unsupported ciphers cause handshake failure, not an untrusted certificate warning.
- ✗
The decryption profile's 'Unsupported Modes' is set to 'Block'
Why it's wrong here
Blocking unsupported modes would cause a connection failure, not an untrusted warning.
- ✗
The decryption policy is not matching the traffic
Why it's wrong here
If the policy didn't match, traffic would not be decrypted and the server would present its own certificate, so no untrusted warning from firewall.
- ✓
The firewall is not configured with the root CA certificate
Why this is correct
Without the full chain, the firewall sends only the server certificate, which browsers may not trust.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCNSA 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 PCNSA exam.