The answer is that traffic will use ISP1 until its route is removed, then use ISP2. This behavior is governed by administrative distance, where FortiGate installs the route with the lowest distance (10) into the routing table as the active path, while the route with distance 20 remains as a floating static backup. When the preferred route via ISP1 fails and is removed from the routing table, the backup route via ISP2 is automatically activated to maintain connectivity. On the Fortinet NSE 4 exam, this concept tests your understanding of static route failover behavior and how unequal distances create a primary-backup relationship, often appearing in questions about redundancy and link failure scenarios. A common trap is assuming both routes load-balance or that the higher-distance route is used immediately upon link degradation, but FortiGate only switches when the primary route is fully removed. Remember: lower distance wins the active slot; higher distance waits in the wings.
NSE4 System and Network Administration Practice Question
This NSE4 practice question tests your understanding of system and network administration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
An admin configures two static routes to the same destination with different distances. The route with distance 10 points to ISP1, and the route with distance 20 points to ISP2. The admin wants to use ISP2 only if ISP1 fails. What is the expected behavior?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
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Traffic will use ISP1 until its route is removed, then use ISP2
When two static routes have different administrative distances, the route with the lower distance (10) is preferred and installed in the routing table. The route with distance 20 remains in the routing table as a backup. If the preferred route (via ISP1) is removed due to a failure, the backup route (via ISP2) is automatically activated. This behavior is fundamental to how FortiGate (and most routers) handle static routes with unequal distances.
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.
Traffic will use ISP1 until its route is removed, then use ISP2
Why this is correct
The lower distance route is preferred; higher distance becomes backup.
Related concept
Read the scenario before looking for a memorised answer.
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The route with distance 20 will be ignored entirely
Why it's wrong here
It will be used if the primary route fails.
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Both routes will be active simultaneously, and the FortiGate will choose based on source IP
Why it's wrong here
Only the route with lowest distance is active in the routing table.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often think both routes are active and load-balancing occurs, but FortiGate only uses the route with the lowest administrative distance unless equal-cost load balancing is explicitly configured.
Detailed technical explanation
How to think about this question
Administrative distance is a trustworthiness metric; FortiGate uses it to select the best route when multiple routes to the same destination exist. The backup route (distance 20) is kept in the routing table but not used until the primary route is removed. In a real-world scenario, if ISP1's next-hop becomes unreachable, the route is removed from the routing table, and the backup route is automatically installed, ensuring failover without manual intervention.
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: Traffic will use ISP1 until its route is removed, then use ISP2 — When two static routes have different administrative distances, the route with the lower distance (10) is preferred and installed in the routing table. The route with distance 20 remains in the routing table as a backup. If the preferred route (via ISP1) is removed due to a failure, the backup route (via ISP2) is automatically activated. This behavior is fundamental to how FortiGate (and most routers) handle static routes with unequal distances.
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.
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Question Discussion
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