VDOM Link Configuration for Inter-VDOM Routing
An administrator configures VDOMs on a FortiGate and assigns port1 to VDOM-A and port2 to VDOM-B. The administrator then creates a firewall policy in VDOM-A to allow traffic from port1 to the VDOM link. Traffic from VDOM-A to VDOM-B is still failing. What is the most likely missing configuration?
Quick Answer
The answer is a VDOM link connecting VDOM-A and VDOM-B. Without this logical interconnecting interface, the two VDOMs remain isolated at Layer 3, so no firewall policy or static route can forward traffic between them, even if policies are correctly configured on each side. On the Fortinet NSE 7 Advanced Security NSE7 exam, this scenario tests your understanding that inter-VDOM routing requires a dedicated VDOM link to establish adjacency, not just separate port assignments and policies. A common trap is assuming that a policy allowing traffic from port1 to the VDOM link is sufficient, but the link itself must first exist as a paired interface spanning both VDOMs. Remember the memory tip: “No link, no link” — without the VDOM link, VDOMs cannot communicate, regardless of firewall rules.
⚠ Common exam trap
Many exam-takers assume a firewall policy alone is sufficient for inter-VDOM traffic, overlooking the mandatory requirement of a VDOM link to create the logical path between VDOMs before any policy or route can be applied.
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 VDOM link connecting VDOM-A and VDOM-B
The most likely missing configuration is a VDOM link, which is the logical interconnecting interface required to route traffic between VDOMs. Without a VDOM link, VDOM-A and VDOM-B are isolated from each other, and no firewall policy or route can forward traffic between them. The administrator must create a VDOM link (e.g., using the 'config system vdom-link' command) to establish the Layer 3 adjacency needed for inter-VDOM communication.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
An inter-VDOM routing policy under system settings
Why it's wrong here
No global inter-VDOM policy exists.
- ✗
A policy in VDOM-B allowing traffic from the VDOM link to port2
Why it's wrong here
The VDOM link itself is missing.
- ✗
A static route in VDOM-A pointing to VDOM-B's subnet
Why it's wrong here
Routing is needed but the VDOM link must exist first.
- ✓
A VDOM link connecting VDOM-A and VDOM-B
Why this is correct
The VDOM link is required for inter-VDOM communication.
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Same concept, more angles
1 more way this is tested on NSE7
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An administrator configures a VDOM on a FortiGate and assigns two interfaces (port1, port2) to it. The administrator wants to route traffic between two different subnets within the same VDOM. Which configuration is required?
medium- A.Configure a VDOM link
- B.Create a policy with inter-VDOM link
- C.Enable inter-VDOM routing
- ✓ D.Configure static or dynamic routing
Why D: Routing between two subnets within the same VDOM is standard intra-VDOM routing. Since both interfaces (port1, port2) belong to the same VDOM, no inter-VDOM constructs are needed; the FortiGate simply requires a route (static or dynamic) to forward packets between the subnets. A firewall policy allowing the traffic is also necessary, but the question specifically asks for the routing configuration.
JA
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.