NSE4 System and Network Administration Practice Question
An administrator notices that traffic to a particular subnet is being load-balanced across two WAN links, but they want all traffic to that subnet to use a single link. Which feature should be configured?
⚠ Common exam trap
It's easy for candidates to confuse ECMP load-balancing with the ability to pin traffic to a single link, mistakenly thinking that adjusting ECMP weights or distances will achieve the same result as policy routing.
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
✓
Policy routing
Policy routing (also called PBR) allows you to override the routing table based on criteria such as source/destination IP, protocol, or port. By configuring a policy route that matches traffic to the specific subnet and sets the output interface to a single WAN link, you can force all that traffic to use one link instead of being load-balanced.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Policy routing
Why this is correct
Policy routing (also called policy-based routing) uses a route map to match specific packet attributes—such as source IP, destination IP, or protocol—and forwards those packets to a defined next-hop or interface, bypassing the normal longest-prefix-match routing table lookup. For traffic to a particular subnet, this allows an administrator to override the default routing decision and force that traffic out a specific interface, which is exactly what the scenario requires.
- ✗
ECMP routing
Why it's wrong here
Equal-Cost Multi-Path (ECMP) routing applies when two or more routes to the same destination have identical metric and administrative distance, causing traffic to be load-balanced across multiple next-hops or interfaces. It does not steer all traffic for a specific subnet to a single chosen interface; instead, it distributes flows among the equal-cost paths, so it cannot enforce a definitive path for that subnet as policy routing would.
- ✗
Static route with higher distance
Why it's wrong here
A static route with a higher administrative distance is less preferred than routes with lower distances, so it is placed in the routing table only if no other route with lower distance exists. When a more specific or more preferred route is already present (for example, from a dynamic protocol or a default static route with lower distance), this higher-distance route will never be used for the subnet, making it ineffective for directing traffic to a particular interface.
- ✗
Route summarization
Why it's wrong here
Route summarization is a technique that aggregates multiple contiguous subnet routes into a single, less-specific route advertisement, reducing the size of routing tables and limiting route propagation across the network. It does not influence the forwarding decision for packets destined to a specific subnet, nor does it direct traffic to a particular interface; rather, it is purely an administrative tool for routing scalability and has no bearing on path selection for an individual subnet.
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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.