The answer is to configure two static default routes with the same distance and metric. This configuration enables Equal-Cost Multi-Path (ECMP) routing on the FortiGate, which allows the device to load-balance outbound traffic across both WAN interfaces by treating the two paths as equally preferred. ECMP load balancing on FortiGate distributes sessions between the ISPs using either a per-flow or per-packet algorithm, ensuring that no single link is overwhelmed. On the Fortinet NSE 4 Network Security Professional exam, this scenario tests your understanding of how route selection and load balancing interact—specifically that ECMP is triggered only when distance and metric are identical, not when they differ. A common trap is to assume policy routing or SD-WAN rules are required, but for basic outbound load balancing, ECMP is the simplest native method. Memory tip: “Same distance, same metric—ECMP is automatic.”
NSE4 System and Network Administration Practice Question
This NSE4 practice question tests your understanding of system and network administration. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network administrator configures a new FortiGate as the default gateway for a subnet. The FortiGate has two WAN interfaces (port1 and port2) connected to different ISPs. The admin wants to load-balance outbound traffic across both links. Which configuration method will achieve this goal?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure two static default routes with the same distance and metric
Option D is correct because configuring two static default routes with the same distance and metric enables ECMP (Equal-Cost Multi-Path) routing on FortiGate. This allows the FortiGate to load-balance outbound traffic across both WAN interfaces (port1 and port2) using a per-flow or per-packet algorithm, distributing sessions between the two ISPs.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Configure a single default gateway and rely on ARP for failover
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse ECMP (same distance/metric) with floating static routes (different distances), mistakenly thinking that multiple default routes with different distances will load-balance, when in fact they only provide failover.
Trap categories for this question
Scenario analysis trap
Different distances create a primary/backup scenario, not load balancing.
Detailed technical explanation
How to think about this question
FortiGate implements ECMP by default when multiple static routes have the same administrative distance and metric. The load-balancing method can be configured under system settings (e.g., source-IP-based or round-robin), and the FortiGate uses session-based distribution to ensure that all packets of a single session follow the same path, avoiding out-of-order delivery. In real-world scenarios, asymmetric routing can occur if return traffic from the internet uses a different ISP, so administrators often pair ECMP with BGP or policy-based routing to control inbound traffic.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
System and Network Administration — This question tests System and Network Administration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Configure two static default routes with the same distance and metric — Option D is correct because configuring two static default routes with the same distance and metric enables ECMP (Equal-Cost Multi-Path) routing on FortiGate. This allows the FortiGate to load-balance outbound traffic across both WAN interfaces (port1 and port2) using a per-flow or per-packet algorithm, distributing sessions between the two ISPs.
What should I do if I get this NSE4 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Variation 1. An administrator is configuring ECMP (Equal-Cost Multi-Path) on a FortiGate. Which TWO conditions are required for ECMP to load balance traffic across multiple routes?
medium
A.Routes must use different next-hop IP addresses
✓ B.Routes must have the same priority setting
✓ C.Routes must have the same administrative distance
D.Routes must be static routes only
E.Routes must be through different interfaces
Why B: Option B is correct because ECMP requires that multiple routes have the same priority (also known as 'distance' in some contexts) to be considered equal-cost. In FortiGate, priority is a metric that determines route preference; only routes with identical priority can be used simultaneously for load balancing. Option C is also correct because administrative distance must be the same for routes to be considered equal; if administrative distances differ, the route with the lower distance is preferred, and ECMP will not apply.
Last reviewed: Jun 24, 2026
Question Discussion
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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.
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