The answer is the application control profile blocking the web application. Even though the firewall policy explicitly allows HTTPS traffic to the web server at 10.0.1.10, the applied application control profile 'Block_Social_Media' is the culprit. This profile is designed to block web-based applications like Facebook and Twitter, and if the web server's login page is served over HTTPS and misclassified by FortiGate’s application control engine—perhaps due to shared CDN infrastructure or similar traffic patterns—the profile will block the HTTPS session, overriding the firewall rule’s permit action. On the Fortinet NSE 4 exam, this scenario tests your understanding that application control profiles operate at Layer 7 and can block traffic even when Layer 3/4 policies allow it, a common trap where candidates focus only on port-based rules. Remember: application control sees the app, not just the port; if the profile blocks the app category, HTTPS alone won’t save you.
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.
Exhibit
Refer to the exhibit.
config firewall policy
edit 1
set name "Web-Server"
set srcintf "port1"
set dstintf "port2"
set srcaddr "all"
set dstaddr "10.0.1.10"
set action accept
set schedule "always"
set service "HTTPS"
set utm-status enable
set ips-sensor "High_Security_Sensor"
set application-list "Block_Social_Media"
next
end
An administrator has configured the policy shown in the exhibit. Traffic to the web server at 10.0.1.10 over HTTPS is allowed, but users complain that they cannot access the web server's login page. The IPS sensor 'High_Security_Sensor' has a signature that blocks SQL injection attempts. The application list 'Block_Social_Media' blocks Facebook and Twitter. What is the most likely cause of the issue?
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.
Refer to the exhibit.
config firewall policy
edit 1
set name "Web-Server"
set srcintf "port1"
set dstintf "port2"
set srcaddr "all"
set dstaddr "10.0.1.10"
set action accept
set schedule "always"
set service "HTTPS"
set utm-status enable
set ips-sensor "High_Security_Sensor"
set application-list "Block_Social_Media"
next
end
A
The IPS sensor is blocking the login page due to a false positive.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The application control profile is blocking the web application.
The policy explicitly allows HTTPS traffic to 10.0.1.10, but the application control profile 'Block_Social_Media' is applied. This profile blocks Facebook and Twitter, which are web-based applications. If the web server's login page is served over HTTPS and is incorrectly classified by the FortiGate as a social media application (e.g., due to shared CDN or similar traffic patterns), the application control profile will block it, preventing user access despite the firewall policy allowing the service.
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 IPS sensor is blocking the login page due to a false positive.
Why it's wrong here
IPS sensor blocks SQL injection, not typical login pages.
✗
The firewall policy action is set to 'deny' but the exhibit shows 'accept'.
Why it's wrong here
The exhibit clearly shows action accept.
✗
The HTTPS service is not correctly defined and blocking the traffic.
Why it's wrong here
The service is set to HTTPS, which is a predefined service, so it should work.
✓
The application control profile is blocking the web application.
Why this is correct
Application control may block the web application if it is misclassified.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume the IPS sensor is the cause of the block, but the question specifies the IPS sensor only blocks SQL injection attempts, not login pages, while the application control profile explicitly blocks social media applications that could be misclassifying the web server's traffic.
Trap categories for this question
Command / output trap
The exhibit clearly shows action accept.
Detailed technical explanation
How to think about this question
FortiGate application control uses deep packet inspection (DPI) to identify applications by their unique signatures, even over encrypted HTTPS. When an application control profile is applied to a policy, it can block or allow traffic based on application identity, overriding the basic service-based allow. In this scenario, the login page might be hosted on a platform that shares infrastructure with social media sites, causing FortiGate to misclassify it as 'Facebook' or 'Twitter' and apply the block. This is a common issue when application control profiles are too broad or when web applications use third-party CDNs or authentication services that match social media signatures.
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: The application control profile is blocking the web application. — The policy explicitly allows HTTPS traffic to 10.0.1.10, but the application control profile 'Block_Social_Media' is applied. This profile blocks Facebook and Twitter, which are web-based applications. If the web server's login page is served over HTTPS and is incorrectly classified by the FortiGate as a social media application (e.g., due to shared CDN or similar traffic patterns), the application control profile will block it, preventing user access despite the firewall policy allowing the service.
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.
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 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.
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.