Question 107 of 516
Securing Traffic and App-IDhardMultiple ChoiceObjective-mapped

How SSL Decryption Affects App-ID Application Identification

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.

Exhibit

show running security-policy
rule 10 {
    name "Allow-Web"
    source any
    destination any
    application ssl
    service application-default
    action allow
}
show session all filter source 10.1.1.100 destination 10.2.2.200
session id 1234, application web-browsing, ...

Refer to the exhibit. A user at 10.1.1.100 reports that they cannot access a website at 10.2.2.200 over HTTPS. The firewall shows the session is allowed with application web-browsing, but the security policy rule "Allow-Web" has application set to ssl. 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.

Exhibit

show running security-policy
rule 10 {
    name "Allow-Web"
    source any
    destination any
    application ssl
    service application-default
    action allow
}
show session all filter source 10.1.1.100 destination 10.2.2.200
session id 1234, application web-browsing, ...

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 SSL decryption policy is not configured.

The session is allowed with application web-browsing, but the security policy rule 'Allow-Web' has application set to ssl. This indicates that the firewall is not decrypting the HTTPS traffic, so App-ID sees only the encrypted TCP handshake and incorrectly identifies it as web-browsing (HTTP) rather than ssl (HTTPS). Without an SSL decryption policy to decrypt the traffic, App-ID cannot inspect the encrypted payload to correctly identify the application as ssl, causing a mismatch between the policy rule's application requirement and the session's identified 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 application override is configured incorrectly.

    Why it's wrong here

    Application override forces a specific app, but the session shows web-browsing, not ssl; this would not cause the mismatch.

  • The security policy rule order is incorrect.

    Why it's wrong here

    The session is allowed, so a rule matched; rule order might affect which rule matches, but the core issue is application identification.

  • The SSL decryption policy is not configured.

    Why this is correct

    Without decryption, App-ID sees only the SSL handshake and identifies the traffic as web-browsing on port 443, not as the more specific ssl application.

    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.

  • The service is set to application-default.

    Why it's wrong here

    The service setting controls port matching, not application identification.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Palo Alto Networks often tests the misconception that a security policy rule with application set to ssl will automatically match HTTPS traffic, but without SSL decryption, App-ID cannot identify the application as ssl, causing the rule to not apply.

Trap categories for this question

  • Command / output trap

    Application override forces a specific app, but the session shows web-browsing, not ssl; this would not cause the mismatch.

Detailed technical explanation

How to think about this question

App-ID relies on decrypted traffic to identify applications like ssl (HTTPS). When SSL decryption is not configured, the firewall sees only the ClientHello and ServerHello messages of the TLS handshake, which are insufficient to distinguish HTTPS from other TCP-based applications. The firewall then falls back to a default classification (often web-browsing for TCP/443) if no other signatures match. In a real-world scenario, this causes security policies that require ssl to fail to match, even though the traffic is HTTPS, leading to connectivity issues for users.

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

Client Server SYN (seq=100) SYN-ACK (seq=200, ack=101) ACK (ack=201) Connection established — data transfer begins

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.

Related practice questions

Related PCNSE practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

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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: The SSL decryption policy is not configured. — The session is allowed with application web-browsing, but the security policy rule 'Allow-Web' has application set to ssl. This indicates that the firewall is not decrypting the HTTPS traffic, so App-ID sees only the encrypted TCP handshake and incorrectly identifies it as web-browsing (HTTP) rather than ssl (HTTPS). Without an SSL decryption policy to decrypt the traffic, App-ID cannot inspect the encrypted payload to correctly identify the application as ssl, causing a mismatch between the policy rule's application requirement and the session's identified 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

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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.