The answer is that the FTD cannot re-encrypt the new connection with the original client certificate, breaking client certificate authentication. When Cisco Firepower Threat Defense performs SSL decryption, it acts as a man-in-the-middle: it terminates the client’s SSL connection, inspects the plaintext, and then initiates a fresh SSL connection to the server. Because the FTD does not have access to the client’s private key, it cannot present the same client certificate to the server during re-encryption, causing the server to reject the connection. This scenario tests your understanding of how SSL decryption breaks client certificate authentication on FTD, a key concept for the Cisco SCOR 350-701 exam. A common trap is assuming that adding the custom port (TCP 8443) to the decryption policy resolves the issue, but the real problem is the inability to re-encrypt with the original certificate. Memory tip: “Decrypts the client, but can’t re-encrypt the client’s identity.”
350-701 Network Security Practice Question
This 350-701 practice question tests your understanding of network security. 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 financial institution uses Cisco Firepower Threat Defense (FTD) for intrusion prevention and SSL decryption. The security team recently enabled SSL decryption on the FTD to inspect encrypted traffic. After the change, some internal applications that use client certificates for authentication stopped working. The FMC shows that SSL decryption is configured to inspect traffic to specific destination IPs. The applications are using a custom port (TCP 8443) for HTTPS. The administrator has already added the custom port to the SSL decryption policy. What is the most likely reason the applications are failing?
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.
The applications are using client certificates, and the FTD is unable to re-encrypt with the original client certificate.
SSL decryption terminates the original SSL session, so client certificates are lost and cannot be passed to the server.
B
The applications are using IPsec, not SSL.
Why wrong: If the applications were using IPsec, SSL decryption would not affect them.
C
The internal CA certificate is not trusted by the FTD.
Why wrong: Even if the CA certificate is trusted, client certificate authentication is still broken because FTD cannot re-encrypt with the original client certificate.
D
The FTD is not configured to inspect traffic on port 8443.
Why wrong: The administrator added the custom port, so inspection should be occurring.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The applications are using client certificates, and the FTD is unable to re-encrypt with the original client certificate.
When FTD performs SSL decryption, it acts as a man-in-the-middle: it terminates the client's SSL connection, inspects the plaintext, and then initiates a new SSL connection to the server. If the client application presents a client certificate for authentication, the FTD cannot re-encrypt the new connection with that same client certificate because it does not have access to the client's private key. The server then rejects the re-encrypted connection, causing the application to fail.
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 applications are using client certificates, and the FTD is unable to re-encrypt with the original client certificate.
Why this is correct
SSL decryption terminates the original SSL session, so client certificates are lost and cannot be passed to the server.
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 applications are using IPsec, not SSL.
Why it's wrong here
If the applications were using IPsec, SSL decryption would not affect them.
✗
The internal CA certificate is not trusted by the FTD.
Why it's wrong here
Even if the CA certificate is trusted, client certificate authentication is still broken because FTD cannot re-encrypt with the original client certificate.
✗
The FTD is not configured to inspect traffic on port 8443.
Why it's wrong here
The administrator added the custom port, so inspection should be occurring.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that adding the custom port to the SSL decryption policy is sufficient, when the real issue is the FTD's inability to re-encrypt with the original client certificate during mutual TLS authentication.
Detailed technical explanation
How to think about this question
In SSL/TLS mutual authentication, the client proves its identity by signing a handshake message with its private key. When FTD decrypts and re-encrypts, it must present a certificate to the server; without the client's private key, it cannot generate the required signature. This is a fundamental limitation of SSL decryption proxies: they can only re-encrypt using a certificate they own (e.g., a re-signing CA), not the original client certificate. In real-world deployments, applications using client certificates often require an SSL bypass rule or an explicit exclusion from decryption.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
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.
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The applications are using client certificates, and the FTD is unable to re-encrypt with the original client certificate. — When FTD performs SSL decryption, it acts as a man-in-the-middle: it terminates the client's SSL connection, inspects the plaintext, and then initiates a new SSL connection to the server. If the client application presents a client certificate for authentication, the FTD cannot re-encrypt the new connection with that same client certificate because it does not have access to the client's private key. The server then rejects the re-encrypted connection, causing the application to fail.
What should I do if I get this 350-701 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.
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 350-701 practice question is part of Courseiva's free Cisco 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 350-701 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.