This NSE4 practice question tests your understanding of security profiles. 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.
An organization uses Application Control to allow only business-critical applications and block social media. The administrator has configured the profile to block Facebook and Twitter, but users can still access Facebook. The firewall policy applies the profile correctly. 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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
SSL inspection is not enabled on the firewall policy.
Application Control relies on SSL inspection to identify applications like Facebook that use HTTPS. Without SSL inspection enabled on the firewall policy, FortiGate can only see encrypted traffic as generic SSL/TLS flows and cannot match the application signatures for Facebook. Enabling SSL inspection (deep inspection or certificate-based inspection) allows the FortiGate to decrypt the traffic and apply the application control profile correctly.
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 control profile is applied to the wrong direction.
Why it's wrong here
The profile is applied correctly per the scenario.
✗
Facebook is not included in the default application signatures.
Why it's wrong here
Facebook is well-known and included.
✓
SSL inspection is not enabled on the firewall policy.
Why this is correct
Without SSL inspection, HTTPS traffic cannot be decrypted and inspected.
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 FortiGate is in flow-based inspection mode.
Why it's wrong here
Flow-based mode supports Application Control.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume application control works on encrypted traffic by default, but FortiGate requires explicit SSL inspection to decrypt and identify HTTPS applications like Facebook.
Trap categories for this question
Scenario analysis trap
The profile is applied correctly per the scenario.
Detailed technical explanation
How to think about this question
FortiGate Application Control uses deep packet inspection (DPI) to match traffic against application signatures. For HTTPS-based applications like Facebook, the FortiGate must perform SSL/TLS interception (decryption) to inspect the payload; otherwise, it only sees encrypted packets and cannot identify the application beyond the SNI field. Even with SNI, the FortiGate may not reliably block the application if the client uses IP-based connections or if the SNI is spoofed, making SSL inspection essential for accurate control.
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.
Security Profiles — This question tests Security Profiles — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: SSL inspection is not enabled on the firewall policy. — Application Control relies on SSL inspection to identify applications like Facebook that use HTTPS. Without SSL inspection enabled on the firewall policy, FortiGate can only see encrypted traffic as generic SSL/TLS flows and cannot match the application signatures for Facebook. Enabling SSL inspection (deep inspection or certificate-based inspection) allows the FortiGate to decrypt the traffic and apply the application control profile correctly.
What should I do if I get this NSE4 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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Question Discussion
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