The answer is that the SMTP traffic is encrypted and deep inspection is not enabled. This is the most likely cause because DLP scanning relies on inspecting the content of data in transit, and when SMTP traffic uses TLS encryption, the FortiGate cannot read the payload without first decrypting it. SSL deep inspection is required to break the TLS tunnel, allowing the DLP sensor to scan for patterns like credit card numbers; without it, the encrypted content passes through undetected. On the Fortinet NSE 4 exam, this scenario tests your understanding of how DLP interacts with encryption—a common trap is assuming DLP works on all traffic by default, but it only applies to unencrypted or decrypted streams. Remember the memory tip: “No decrypt, no detect”—if traffic is encrypted, deep inspection must be enabled for DLP to function.
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 configured a DLP profile to detect credit card numbers in outgoing emails. The profile is applied to an outbound SMTP policy. Users report that emails with credit card numbers are still being sent successfully. 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.
The DLP profile is set to 'monitor' instead of 'block'
Why wrong: Monitor would still detect and log, but the question states it is not detecting at all.
B
The DLP profile is not applied to the correct policy
Why wrong: The question states it is applied to an outbound SMTP policy.
C
The credit card number pattern is not correctly defined
Why wrong: While possible, the most common issue is encryption blocking visibility.
D
The SMTP traffic is encrypted and deep inspection is not enabled
If SMTP over TLS is used, the FortiGate cannot inspect the email content without SSL deep inspection decrypting the traffic. DLP will not detect the credit card numbers.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The SMTP traffic is encrypted and deep inspection is not enabled
DLP scanning requires deep inspection if the traffic is encrypted. If SMTP traffic is encrypted with TLS (SMTPS), the FortiGate needs SSL deep inspection to decrypt and inspect the content. Without it, DLP cannot see the credit card numbers.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 DLP profile is set to 'monitor' instead of 'block'
Why it's wrong here
Monitor would still detect and log, but the question states it is not detecting at all.
✗
The DLP profile is not applied to the correct policy
Why it's wrong here
The question states it is applied to an outbound SMTP policy.
✗
The credit card number pattern is not correctly defined
Why it's wrong here
While possible, the most common issue is encryption blocking visibility.
✓
The SMTP traffic is encrypted and deep inspection is not enabled
Why this is correct
If SMTP over TLS is used, the FortiGate cannot inspect the email content without SSL deep inspection decrypting the traffic. DLP will not detect the credit card numbers.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related NSE4 NAT questions on configuration and troubleshooting.
Security Profiles — This question tests Security Profiles — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The SMTP traffic is encrypted and deep inspection is not enabled — DLP scanning requires deep inspection if the traffic is encrypted. If SMTP traffic is encrypted with TLS (SMTPS), the FortiGate needs SSL deep inspection to decrypt and inspect the content. Without it, DLP cannot see the credit card numbers.
What should I do if I get this NSE4 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related NSE4 NAT questions on configuration and troubleshooting.
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?
Static NAT maps one inside address to one outside address.
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. An administrator configures a DLP profile to detect credit card numbers in email traffic. The DLP rule uses a regular expression. However, the DLP sensor is not triggering on emails containing credit card numbers. What is a likely reason?
hard
✓ A.SSL deep inspection is not enabled on the policy
B.The regular expression is case-sensitive and credit card numbers are lowercase
C.The DLP sensor is configured to 'monitor' only
D.The DLP profile is applied to the inbound policy only
Why A: DLP sensors operate on traffic that has been decrypted if necessary. If the email is sent over TLS, the FortiGate needs SSL deep inspection to see the email content. Also, the DLP sensor needs to be applied to the correct direction (e.g., both send and receive).
Variation 2. An administrator configures a DLP sensor to detect credit card numbers in traffic. However, the sensor is not detecting any credit card numbers even though they are present in emails. What could be the reason?
medium
✓ A.Email traffic is encrypted and SSL deep inspection is not enabled
B.The DLP sensor is applied to the wrong policy
C.The credit card regular expression is incorrect
D.The DLP sensor is in 'Monitor' mode
Why A: DLP sensors inspect traffic content. If the traffic is encrypted (e.g., via TLS), the sensor cannot see the plaintext unless SSL deep inspection is enabled to decrypt the traffic first.
Last reviewed: Jun 21, 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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