- A
The App-ID signature database is outdated.
Why wrong: Outdated signatures cause misidentification, not 'incomplete' classification.
- B
The security policy does not have an allow rule for web-browsing.
Why wrong: Lack of allow rule would drop traffic, not classify as incomplete.
- C
The firewall is experiencing asymmetric routing.
Why wrong: Asymmetric routing can cause incomplete but is less common for web traffic.
- D
SSL decryption is not enabled for the traffic.
Without SSL decryption, encrypted traffic cannot be fully inspected, leading to 'incomplete' App-ID.
Question 451 of 516
Why Does App-ID Show 'Incomplete' for Web-Browsing?
This PCNSE practice question tests your understanding of securing traffic and app-id. 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 network administrator notices that web-browsing traffic is being classified as 'incomplete' in the App-ID table. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
✓
SSL decryption is not enabled for the traffic.
When SSL decryption is not enabled, the firewall cannot inspect encrypted HTTPS traffic payloads. As a result, App-ID may classify the traffic as 'incomplete' because it cannot match the encrypted payload to the web-browsing application signature. Enabling SSL decryption allows the firewall to decrypt the traffic, inspect the payload, and correctly identify the application.
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.
- ✗
The App-ID signature database is outdated.
Why it's wrong here
Outdated signatures cause misidentification, not 'incomplete' classification.
- ✗
The security policy does not have an allow rule for web-browsing.
Why it's wrong here
Lack of allow rule would drop traffic, not classify as incomplete.
- ✗
The firewall is experiencing asymmetric routing.
Why it's wrong here
Asymmetric routing can cause incomplete but is less common for web traffic.
- ✓
SSL decryption is not enabled for the traffic.
Why this is correct
Without SSL decryption, encrypted traffic cannot be fully inspected, leading to 'incomplete' App-ID.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
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 assume 'incomplete' means a policy or signature issue, when in fact it specifically indicates that App-ID could not gather enough data from the encrypted session to complete identification, pointing directly to SSL decryption as the root cause.
Detailed technical explanation
How to think about this question
App-ID uses multiple mechanisms to identify applications, including protocol decoding, signature matching, and behavioral analysis. For HTTPS traffic, the firewall must decrypt the SSL/TLS handshake and payload to inspect the HTTP headers and content; without decryption, only the Server Name Indication (SNI) or IP address may be available, which is often insufficient for accurate identification, leading to an 'incomplete' status. In a real-world scenario, if a firewall is configured to decrypt traffic but the decryption policy excludes certain traffic (e.g., due to certificate pinning or decryption exceptions), that traffic may also appear as 'incomplete'.
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Securing Traffic and App-ID — study guide chapter
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FAQ
Questions learners often ask
What does this PCNSE question test?
Securing Traffic and App-ID — This question tests Securing Traffic and App-ID — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: SSL decryption is not enabled for the traffic. — When SSL decryption is not enabled, the firewall cannot inspect encrypted HTTPS traffic payloads. As a result, App-ID may classify the traffic as 'incomplete' because it cannot match the encrypted payload to the web-browsing application signature. Enabling SSL decryption allows the firewall to decrypt the traffic, inspect the payload, and correctly identify the application.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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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