NSE4 System and Network Administration Practice Question
A FortiGate is operating in transparent mode. The admin needs to allow HTTP traffic from users to a web server. Which type of firewall policy is required?
⚠ Common exam trap
A common mix-up: candidates assume firewall policies always involve IP addresses and routing, but in transparent mode, the FortiGate uses Layer 2 policies that operate at the data link layer, not the network layer.
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
✓
A layer 2 firewall policy
In transparent mode, the FortiGate operates as a Layer 2 bridge, forwarding traffic without routing. To allow HTTP traffic from users to a web server, a Layer 2 firewall policy is required because it filters traffic based on MAC addresses and Layer 2 headers, not IP addresses or routing decisions. This policy type is the only one that works in transparent mode, as it does not involve NAT or routing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
A layer 2 firewall policy
Why this is correct
In transparent mode, the FortiGate acts as a transparent bridge (bump in the wire) and does not route IP traffic, so all traffic control must occur at Layer 2. A layer 2 firewall policy inspects and forwards frames based on MAC addresses, VLANs, and other Layer 2 attributes, making it the only policy type that can effectively filter traffic in this deployment. This policy type is required because there is no Layer 3 routing table or IP-based decision-making in transparent mode.
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A policy-based NAT rule
Why it's wrong here
Policy-based NAT rules are designed to perform source or destination IP translation, which requires the FortiGate to function as a Layer 3 router with routing decisions. In transparent mode, the FortiGate bridges frames without modifying IP addresses, so NAT is inherently unsupported and cannot be applied. A policy-based NAT rule would be invalid because it relies on routing and IP header modifications that do not exist in a Layer 2 forwarding path.
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A firewall policy using zone-based security
Why it's wrong here
While FortiGate allows interfaces to be grouped into zones even in transparent mode, the policy itself is still a Layer 2 policy because traffic forwarding is based on MAC addresses and VLANs, not IP addresses. Zone-based security as a distinct policy concept is used in NAT/Route mode where Layer 3 policies are applied to zone pairs. In transparent mode, the zone is simply a collection of Layer 2 interfaces, and the policy remains Layer 2, so this answer misidentifies the actual policy type.
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A VIP policy to map the web server's public IP
Why it's wrong here
A VIP (Virtual IP) policy is used for port forwarding and destination NAT, mapping an external public IP to an internal private IP, which requires the FortiGate to route and translate IP traffic. Transparent mode does not perform routing or NAT, as it operates at Layer 2 and forwards frames without rewriting IP addresses. Therefore, a VIP policy cannot be used in transparent mode and is only applicable in NAT/Route mode, making this option incorrect.
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
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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.