The correct answer is to use deep inspection and add the application's self-signed certificate to the FortiGate's trusted CA list. This is required because deep inspection performs full SSL/TLS decryption, allowing the FortiGate to inspect the payload of traffic on a non-standard port like 9443, whereas certificate inspection only validates metadata without decrypting. When a self-signed certificate is used, the FortiGate’s proxy cannot validate it against a public CA, so you must explicitly import that certificate into the trusted CA store to avoid connection drops. On the Fortinet NSE 4 exam, this scenario tests your understanding of the difference between certificate inspection and deep inspection, and it often appears as a trap where candidates mistakenly choose certificate inspection for non-standard ports. Remember the key distinction: certificate inspection is for metadata only, deep inspection is for full decryption. A helpful memory tip is “Deep for decrypt, self-signed needs trust.”
NSE4 Security Profiles Practice Question
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 administrator wants to inspect SSL traffic to a specific finance application that uses a custom port (9443) and a self-signed certificate. Which configuration is required?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use deep inspection and add the application's self-signed certificate to the FortiGate's trusted CA list.
Option C is correct because deep inspection is required to decrypt and inspect SSL traffic using a self-signed certificate on a non-standard port. The FortiGate must trust the application's self-signed certificate by adding it to the trusted CA list; otherwise, the deep inspection proxy will fail to validate the certificate and drop the connection. Certificate inspection (Option A) only checks the certificate metadata without decrypting the payload, so it cannot inspect the actual application traffic.
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.
✗
Configure certificate inspection on the policy.
Why it's wrong here
Certificate inspection does not decrypt traffic.
✗
Disable SSL inspection for that application.
Why it's wrong here
That would bypass inspection.
✓
Use deep inspection and add the application's self-signed certificate to the FortiGate's trusted CA list.
Why this is correct
Deep inspection decrypts and re-encrypts; trusted CA list allows self-signed certs.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use flow-based inspection with certificate inspection.
Why it's wrong here
Flow-based inspection does not decrypt deep.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse certificate inspection with deep inspection, assuming certificate inspection can decrypt traffic, when in fact only deep inspection performs full decryption and is required for self-signed certificates on non-standard ports.
Detailed technical explanation
How to think about this question
Deep inspection on FortiGate uses a proxy to terminate the SSL/TLS connection, re-encrypting it with a FortiGate-generated certificate. For self-signed certificates, the FortiGate must have the server's certificate imported as a trusted CA to avoid certificate validation failures. This is configured under System > Certificates > CA Certificates, and the inspection mode must be set to 'deep inspection' in the SSL/SSH inspection profile applied to the firewall policy.
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 NSE4 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.
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: Use deep inspection and add the application's self-signed certificate to the FortiGate's trusted CA list. — Option C is correct because deep inspection is required to decrypt and inspect SSL traffic using a self-signed certificate on a non-standard port. The FortiGate must trust the application's self-signed certificate by adding it to the trusted CA list; otherwise, the deep inspection proxy will fail to validate the certificate and drop the connection. Certificate inspection (Option A) only checks the certificate metadata without decrypting the payload, so it cannot inspect the actual application traffic.
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.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network administrator notices that HTTP traffic is being scanned by the antivirus profile, but HTTPS traffic to the same web server is not being scanned. The firewall policy has the antivirus profile applied and SSL inspection is set to 'certificate-inspection'. What is the most likely reason HTTPS traffic is not being scanned?
medium
✓ A.Certificate inspection does not decrypt the traffic, so the antivirus scanner cannot inspect the payload.
B.The antivirus profile is configured in flow mode, which does not support scanning HTTPS traffic.
C.The web server is not using a cipher supported by the FortiGate.
D.The FortiGate is using proxy-based inspection, which does not support HTTPS scanning.
Last reviewed: Jun 11, 2026
Question Discussion
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This NSE4 practice question is part of Courseiva's free Fortinet 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 NSE4 exam.
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