NSE4 Firewall Policies and NAT Practice Question
An administrator wants to limit the bandwidth for a specific application (e.g., YouTube) across all users. The administrator creates a traffic shaper and applies it to the firewall policy. What additional configuration is needed to identify YouTube traffic?
⚠ Common exam trap
Candidates often confuse URL filtering (which identifies web domains) with Application Control (which identifies applications by their network behavior), leading them to choose deep inspection and URL filtering instead of the correct Application Control profile.
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
✓
Apply an Application Control profile to the policy
Application Control profiles are specifically designed to identify and control traffic based on application signatures, such as YouTube. A traffic shaper limits bandwidth, but it requires an Application Control profile to classify the traffic as YouTube before the shaping can be applied. Without this profile, the firewall cannot distinguish YouTube from other web traffic.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable deep inspection and create a URL filter
Why it's wrong here
Deep inspection decrypts SSL/TLS traffic to allow security inspection, while URL filtering blocks or allows websites based on URL categories or domain names. Neither of these mechanisms applies bandwidth limits or traffic shaping; they are access-control features. To manage bandwidth for a specific application, you need a traffic shaper triggered by application control, not by URL or content inspection.
- ✗
Create a custom service object for YouTube
Why it's wrong here
A custom service object in FortiOS is used to match traffic based on IP protocol and port numbers, such as TCP/443. YouTube traffic uses standard web ports shared with thousands of other applications, so a service object cannot isolate YouTube as an application. Bandwidth limiting requires application-level identification via Application Control signatures, not a service definition.
- ✗
Use a geography object to block non-local traffic
Why it's wrong here
Geography objects match traffic by the country associated with a source or destination IP address, allowing you to block traffic from specific regions. Blocking non-local traffic would affect all applications originating from those regions, not just YouTube, and it does not provide any bandwidth control. This is a connection restriction based on geolocation, not a traffic-shaping rule for an application.
- ✓
Apply an Application Control profile to the policy
Why this is correct
Applying an Application Control profile to the FortiGate policy identifies traffic by application signatures rather than by IP, protocol, or country. Once YouTube is identified, you can attach a traffic shaper to that policy (or use per-application bandwidth limits in the profile) to enforce a maximum bandwidth. This is the correct method because it targets the application while allowing other traffic to remain unaffected.
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JA
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.