PCNSA App-ID and Content-ID Practice Question
A company has a security policy that allows 'ssl' application but does not have SSL decryption enabled. What can App-ID still identify from the encrypted session?
⚠ Common exam trap
A common mix-up: candidates assume all encrypted traffic is opaque to App-ID, but the SNI field remains visible and can be used for application identification, which is a key distinction tested in the PCNSA exam.
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 SNI (Server Name Indication).
App-ID can identify the SNI (Server Name Indication) from an encrypted session because the SNI is sent in cleartext during the TLS handshake, before encryption begins. This allows the firewall to determine the destination hostname without decrypting the traffic, enabling policy enforcement based on the application or domain even when SSL decryption is disabled.
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 SNI (Server Name Indication).
Why this is correct
Without decryption, App-ID reads the TLS ClientHello, which is sent in cleartext, and extracts the SNI field to identify the destination hostname. This satisfies the stem's constraint of allowing the ssl application while decryption remains disabled, letting App-ID distinguish encrypted sessions by server name.
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The exact URL being accessed.
Why it's wrong here
Without decryption, App-ID reads only the TLS handshake metadata, such as the server certificate and SNI, so it cannot see the full URL path or query string. It is tempting because SNI often exposes the hostname, but the exact URL requires decryption.
- ✗
The file type being transferred.
Why it's wrong here
File type is determined by inspecting payload content or MIME headers, both encrypted inside the TLS session. App-ID cannot see them without decryption. File blocking is the correct control when decryption is enabled and the firewall can inspect transferred content.
- ✗
The client and server IP addresses.
Why it's wrong here
App-ID identifies applications, not addressing; IP addresses come from packet headers regardless of App-ID. The question asks what App-ID identifies, and the answer is the application, derived from TLS handshake attributes such as the server certificate and SNI, not the client and server addresses.
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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.