NSE7 Enterprise Firewall and VDOMs Practice Question
A FortiGate in transparent mode with multiple VDOMs is deployed at a customer site. The customer reports that traffic between two VLANs on the same physical segment is not being forwarded. The administrator verifies that the firewall policies are configured correctly. What is the most likely cause?
⚠ Common exam trap
Candidates often assume transparent mode FortiGates can route between VLANs automatically, forgetting that VLAN interfaces must be explicitly created to enable Layer 2 forwarding between VLANs on the same physical segment.
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 FortiGate is in transparent mode and does not route between VLANs without a VLAN interface
In transparent mode, a FortiGate acts as a Layer 2 bridge and does not perform IP routing. To forward traffic between VLANs on the same physical segment, you must create VLAN subinterfaces on the FortiGate and assign them to the appropriate VDOMs. Without these VLAN interfaces, the FortiGate cannot distinguish or forward traffic between the VLANs, even if firewall policies are correctly configured.
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 VDOMs are not configured with management IP addresses
Why it's wrong here
Management IPs are for administrative access, not for forwarding traffic.
- ✓
The FortiGate is in transparent mode and does not route between VLANs without a VLAN interface
Why this is correct
Transparent mode requires VLAN subinterfaces and policies to allow inter-VLAN traffic, and by default does not route.
- ✗
The VDOM limit has been exceeded
Why it's wrong here
VDOM limit would affect creation, not forwarding.
- ✗
Inter-VDOM routing is disabled between the VDOMs
Why it's wrong here
The traffic is within the same VDOM if both VLANs are in the same VDOM.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This NSE7 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 NSE7 exam.