PCNSE Securing Traffic and App-ID Practice Question
When configuring a custom application signature, which field is mandatory to define the application?
⚠ Common exam trap
Watch out — candidates often assume Port is mandatory because of traditional firewall rules, but Palo Alto Networks App-ID is designed to identify applications regardless of port, making Protocol the only mandatory field for custom signatures.
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
✓
Protocol
In Palo Alto Networks App-ID, when creating a custom application signature, the Protocol field is mandatory because App-ID uses protocol detection as the first step to identify traffic. Without specifying the protocol (e.g., TCP, UDP, or a specific protocol number), the firewall cannot associate the signature with the correct traffic stream, making the application definition incomplete.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Category
Why it's wrong here
Category is for organization, not mandatory.
- ✓
Protocol
Why this is correct
Protocol is required for the firewall to know which signatures to apply.
- ✗
Port
Why it's wrong here
Port can be left blank if using a protocol decoder.
- ✗
Subcategory
Why it's wrong here
Subcategory is optional.
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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.