Question 78 of 516
Decryption and SSL InspectionmediumMultiple SelectObjective-mapped

PCNSE Decryption and SSL Inspection Practice Question

This PCNSE practice question tests your understanding of decryption and ssl inspection. 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.

Which TWO conditions typically cause the firewall to bypass SSL decryption for a session? (Choose two.)

Question 1mediummulti select
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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 client and server negotiate a cipher suite not supported by the firewall.

Option B is correct because if the client and server negotiate a cipher suite that the firewall does not support, the firewall cannot decrypt the session. The firewall must be able to inspect the SSL/TLS handshake and match the cipher suite to its supported list; if the cipher suite is unsupported (e.g., TLS 1.3-only ciphers on an older firewall), decryption fails and the session is bypassed. Option C is correct because when the server presents an invalid certificate (expired, untrusted, or mismatched), the firewall cannot complete the SSL handshake with the client, so it bypasses decryption to avoid breaking the session.

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 firewall detects that the session is already decrypted (e.g., by another device).

    Why it's wrong here

    The firewall does not detect if traffic is already decrypted; it will attempt decryption.

  • The client and server negotiate a cipher suite not supported by the firewall.

    Why this is correct

    If the cipher is unsupported, the firewall cannot decrypt.

    Related concept

    Read the scenario before looking for a memorised answer.

  • The certificate presented by the server is not valid (e.g., expired, untrusted).

    Why this is correct

    If certificate validation fails, the firewall may bypass decryption to avoid breaking connectivity.

    Related concept

    Read the scenario before looking for a memorised answer.

  • The traffic matches a 'no-decrypt' rule in the decryption policy.

    Why it's wrong here

    That is a policy-based bypass, not a condition; the question asks for conditions.

  • The decrypted data exceeds a certain size threshold.

    Why it's wrong here

    Size does not cause bypass; the firewall will still decrypt.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often confuse policy-based 'no-decrypt' rules (which are intentional exclusions) with technical conditions that force a bypass, or they mistakenly think that invalid certificates always cause decryption to fail when in fact the firewall can be configured to still decrypt with a warning or to bypass based on policy.

Detailed technical explanation

How to think about this question

During the SSL/TLS handshake, the firewall acts as a man-in-the-middle (MITM) proxy, terminating the client connection and initiating a new one to the server. If the cipher suite negotiated between client and server is not in the firewall's supported cipher list (e.g., the firewall only supports up to TLS 1.2 with specific ciphers, but the client and server negotiate TLS 1.3 with AEAD-only ciphers), the firewall cannot decrypt the traffic and must bypass the session. Similarly, certificate validation failures (e.g., expired or untrusted CA) prevent the firewall from generating a valid re-signed certificate for the client, forcing a bypass to avoid a certificate error that would break the user experience.

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.

Related practice questions

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FAQ

Questions learners often ask

What does this PCNSE question test?

Decryption and SSL Inspection — This question tests Decryption and SSL Inspection — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The client and server negotiate a cipher suite not supported by the firewall. — Option B is correct because if the client and server negotiate a cipher suite that the firewall does not support, the firewall cannot decrypt the session. The firewall must be able to inspect the SSL/TLS handshake and match the cipher suite to its supported list; if the cipher suite is unsupported (e.g., TLS 1.3-only ciphers on an older firewall), decryption fails and the session is bypassed. Option C is correct because when the server presents an invalid certificate (expired, untrusted, or mismatched), the firewall cannot complete the SSL handshake with the client, so it bypasses decryption to avoid breaking the session.

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: Jun 25, 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.