The correct conclusion is that a large number of decryption sessions are failing due to a TLS version mismatch. This occurs when the client and server attempt to negotiate different TLS protocol versions—for example, a client offering only TLS 1.0 while the server requires TLS 1.2—causing the Palo Alto Networks firewall to log a specific decryption failure reason in its session table. On the PCNSA exam, this scenario tests your ability to interpret decryption logs and distinguish between common failure types like certificate errors, policy blocks, and version mismatches. A frequent trap is assuming all decryption failures stem from invalid certificates, but the exhibit’s explicit “TLS version mismatch” error points directly to protocol incompatibility. Remember the mnemonic “Version Variance = Decryption Dissonance” to recall that mismatched TLS versions, not certificates, are the root cause here.
PCNSA Decryption and Monitoring Practice Question
This PCNSA practice question tests your understanding of decryption and monitoring. 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
Refer to the exhibit.
# show system info | match decrypt
Decryption status: enabled
Decryption sessions: 523 (current), 1024 (peak)
Certificate errors: 12 (since last hour)
# show decryption statistics
Policy hits: Decrypt: 1500, No Decrypt: 300
TLS version failures: 5 (TLS 1.0: 3, TLS 1.1: 2)
Refer to the exhibit. An administrator notices a large number of decryption sessions. What is a valid conclusion based on the output?
Refer to the exhibit.
# show system info | match decrypt
Decryption status: enabled
Decryption sessions: 523 (current), 1024 (peak)
Certificate errors: 12 (since last hour)
# show decryption statistics
Policy hits: Decrypt: 1500, No Decrypt: 300
TLS version failures: 5 (TLS 1.0: 3, TLS 1.1: 2)
A
The firewall is rejecting many sessions due to certificate errors.
Why wrong: Only 12 errors in the last hour, not 'many'.
B
There are a few sessions failing due to TLS version mismatch.
5 TLS version failures indicate some issues.
C
The decryption policy is not being hit because of low policy hits.
Why wrong: Policy hits are 1800 total, indicating active usage.
D
The current decryption session count is at its peak.
Why wrong: Current is 523, peak is 1024, so not at peak.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
There are a few sessions failing due to TLS version mismatch.
The exhibit shows decryption sessions with a 'TLS version mismatch' error, which indicates that the firewall is failing to establish a decryption session because the client and server are attempting to use different TLS versions (e.g., TLS 1.0 vs. TLS 1.2). This is a specific failure reason logged in the decryption session table, and the large number of such sessions confirms that many are failing due to this mismatch, not due to certificate errors or policy issues.
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 is rejecting many sessions due to certificate errors.
Why it's wrong here
Only 12 errors in the last hour, not 'many'.
✓
There are a few sessions failing due to TLS version mismatch.
Read the scenario before looking for a memorised answer.
✗
The decryption policy is not being hit because of low policy hits.
Why it's wrong here
Policy hits are 1800 total, indicating active usage.
✗
The current decryption session count is at its peak.
Why it's wrong here
Current is 523, peak is 1024, so not at peak.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Palo Alto Networks often tests the ability to distinguish between different decryption failure reasons (TLS version mismatch vs. certificate errors vs. cipher mismatch), and the trap here is that candidates may assume any decryption failure is due to certificate issues, ignoring the specific error message in the output.
Detailed technical explanation
How to think about this question
TLS version mismatch occurs when the firewall's decryption proxy negotiates a TLS version with the client that differs from the version the server supports or offers. For example, if the client offers TLS 1.2 but the server only supports TLS 1.0, the firewall cannot complete the handshake and logs the mismatch. This is distinct from cipher mismatch or certificate errors, and it often requires adjusting the firewall's decryption profile to allow a broader range of TLS versions or to use a forward proxy that can renegotiate.
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 PCNSA 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.
Decryption and Monitoring — This question tests Decryption and Monitoring — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: There are a few sessions failing due to TLS version mismatch. — The exhibit shows decryption sessions with a 'TLS version mismatch' error, which indicates that the firewall is failing to establish a decryption session because the client and server are attempting to use different TLS versions (e.g., TLS 1.0 vs. TLS 1.2). This is a specific failure reason logged in the decryption session table, and the large number of such sessions confirms that many are failing due to this mismatch, not due to certificate errors or policy issues.
What should I do if I get this PCNSA 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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This PCNSA 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 PCNSA exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.