- A
Modify the security policy rule to allow 'unknown-tcp'.
Why wrong: Allowing unknown-tcp would permit the traffic but still not identify the application.
- B
Update the application and threat signatures.
Why wrong: If the application is brand new, it may not be in the signature database yet; updating might help, but the question assumes it's a custom app.
- C
Disable application identification on the zone.
Why wrong: Disabling application identification would make all traffic unknown, which is counterproductive.
- D
Create an application override for the application.
An application override allows the firewall to identify traffic based on port and IP criteria, useful for custom applications.
Question 229 of 516
Application Not Identified? Resolve Unknown-TCP with Application Override
This PCNSE practice question tests your understanding of troubleshoot. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A new application is not being identified by the firewall. Traffic for the application is being treated as 'unknown-tcp'. Which action should be taken to resolve this?
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
✓
Create an application override for the application.
When a firewall fails to identify an application and treats its traffic as 'unknown-tcp', the most direct and efficient solution is to create an application override. This manually maps the traffic (based on IP/port/protocol) to the correct application, bypassing the firewall's signature-based identification. Option D is correct because it immediately resolves the misclassification without waiting for signature updates or weakening security by broadly allowing unknown traffic.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Modify the security policy rule to allow 'unknown-tcp'.
Why it's wrong here
Allowing unknown-tcp would permit the traffic but still not identify the application.
- ✗
Update the application and threat signatures.
Why it's wrong here
If the application is brand new, it may not be in the signature database yet; updating might help, but the question assumes it's a custom app.
- ✗
Disable application identification on the zone.
Why it's wrong here
Disabling application identification would make all traffic unknown, which is counterproductive.
- ✓
Create an application override for the application.
Why this is correct
An application override allows the firewall to identify traffic based on port and IP criteria, useful for custom applications.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose 'Update the application and threat signatures' (Option B) thinking it's the standard fix, but the question implies the application is new or custom and may never be identified by signatures, making an application override the correct immediate solution.
Detailed technical explanation
How to think about this question
An application override creates a static mapping in the firewall's application database, matching traffic by source/destination IP, port, and protocol to a user-defined application. This is particularly useful for proprietary or legacy applications that use non-standard ports or encrypted payloads that evade signature-based detection. Under the hood, the override takes precedence over App-ID's heuristic and signature analysis, ensuring the traffic is immediately classified correctly for policy enforcement and logging.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the PCNSE exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Visual reference
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PCNSE question test?
Troubleshoot — This question tests Troubleshoot — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create an application override for the application. — When a firewall fails to identify an application and treats its traffic as 'unknown-tcp', the most direct and efficient solution is to create an application override. This manually maps the traffic (based on IP/port/protocol) to the correct application, bypassing the firewall's signature-based identification. Option D is correct because it immediately resolves the misclassification without waiting for signature updates or weakening security by broadly allowing unknown traffic.
What should I do if I get this PCNSE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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.
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