NSE4 Security Profiles Practice Question
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
endAn 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?
⚠ Common exam trap
Test-takers frequently 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.
Answer choices
Why each option matters
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.
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
An IPS sensor inspects for known attack patterns such as SQL injection or cross-site scripting; a standard HTTPS login page is not malicious traffic. Even if a false positive occurred, the exhibit would show the session denied by the IPS sensor log, not an application control banner; the policy configuration references an application control profile, which is what performs deep inspection on application signatures. The issue specifically lies with application control classification, not intrusion prevention.
- ✗
The firewall policy action is set to 'deny' but the exhibit shows 'accept'.
Why it's wrong here
The exhibit displays an explicit 'Action: ACCEPT' setting in the policy; therefore, the deny hypothesis contradicts the shown configuration. If the action were deny, all matching traffic would be dropped before reaching any profile, but the actual problem is that traffic is allowed yet the web application is being blocked by a security profile. Thus, the issue is not the base policy action.
- ✗
The HTTPS service is not correctly defined and blocking the traffic.
Why it's wrong here
HTTPS is a built-in predefined service in FortiOS, mapped to TCP port 443, and the policy references it correctly. A misdefined service would cause a port mismatch or the policy not matching at all, but here the session matches the policy and reaches the application control profile. The traffic is being permitted and then classified, so the service definition is not the cause.
- ✓
The application control profile is blocking the web application.
Why this is correct
The application control profile is the only profile configured in the policy that can identify and block specific web applications by their signatures, even when the underlying HTTP/HTTPS service is valid. When a user attempts to access the login page, the FortiGate can classify the traffic as a known application and apply the profile's 'block' action, denying the request. This is a common cause of access failure when the base policy action is accept and HTTPS is correctly defined.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.