NSE7 ABR (Area Border Router) Practice Question
An administrator has configured OSPF on a FortiGate with multiple areas. They want to ensure that routes from area 0 are redistributed into area 1, but they notice that routes from area 1 are not appearing in area 0. What is the most likely configuration issue?
⚠ Common exam trap
The trap is that candidates often assume that any router connecting area 1 to area 0 is automatically an ABR, but it must have an interface in area 0 to function as an ABR. Without it, the router cannot perform inter-area route advertisement.
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 ABR is not configured with 'area 0' and 'area 1' on the same router
The most likely configuration issue is that the ABR is not properly configured as an ABR – it must have interfaces in both area 0 and area 1. Without an interface in area 0, the router cannot generate Type 3 LSAs (inter-area advertisements) between the areas, so routes from area 1 never appear in area 0. Option B is incorrect because a stub area blocks Type 5 LSAs from entering the stub area, but it does not block Type 3 LSAs from being advertised out of the stub area into the backbone; therefore, stub configuration would not prevent inter-area routes from reaching area 0.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
There is a firewall policy blocking OSPF packets
Why it's wrong here
Incorrect. While firewall policies could block OSPF, it would affect all OSPF communication, not just routes from area 1. The specific symptom suggests an OSPF configuration issue, not a policy blocking packets.
- ✗
The ABR has 'area 1 stub' configured, preventing LSA type 5 redistribution
Why it's wrong here
Incorrect. Configuring area 1 as a stub area blocks Type 5 LSAs from entering area 1, but it does not prevent Type 3 LSAs (inter-area routes) from being advertised from area 1 into area 0. Therefore, stub configuration is not the likely cause.
- ✗
The redistribution is done with a route map that is not permitting the routes
Why it's wrong here
Incorrect. If redistribution is involved, a route map could filter routes, but the question does not mention redistribution; the issue is inter-area routing, which relies on Type 3 LSAs generated by the ABR.
- ✓
The ABR is not configured with 'area 0' and 'area 1' on the same router
Why this is correct
Correct. For a router to act as an ABR and exchange routes between areas, it must have interfaces in both area 0 and the other area (area 1). If the router lacks an interface in area 0, it cannot generate Type 3 LSAs, and routes from area 1 will not appear in area 0.
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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.