The answer is that the gateway 203.0.113.1 on port1 is unreachable. When a FortiGate has multiple default routes, it selects the route with the lowest administrative distance as the primary path, and all traffic to 8.8.8.8 is sent through that gateway. If that gateway is unreachable—meaning the FortiGate cannot resolve its MAC address via ARP or the next-hop interface is down—the route becomes inactive, and the secondary default route is not automatically used for traffic sourced from the FortiGate itself, such as a CLI ping. This scenario tests your understanding of how FortiGate handles multiple default routes and gateway reachability, a common trap on the Fortinet NSE 4 Network Security Professional NSE4 exam where candidates assume a backup route will take over immediately. The key is that the FortiGate does not fail over to the secondary default route unless the primary route’s gateway is confirmed dead via link status or route health checking. Memory tip: think “primary path, primary problem”—if the best route’s next hop is down, the ping fails regardless of other routes.
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.
Exhibit
Refer to the exhibit.
config router static
edit 1
set device port1
set gateway 203.0.113.1
set dst 0.0.0.0 0.0.0.0
set distance 10
next
edit 2
set device port2
set gateway 10.0.0.1
set dst 0.0.0.0 0.0.0.0
set distance 20
next
end
Refer to the exhibit. The FortiGate has two default routes. The administrator attempts to ping 8.8.8.8 from the CLI and receives no response. What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
config router static
edit 1
set device port1
set gateway 203.0.113.1
set dst 0.0.0.0 0.0.0.0
set distance 10
next
edit 2
set device port2
set gateway 10.0.0.1
set dst 0.0.0.0 0.0.0.0
set distance 20
next
end
A
The second route is overwriting the first route
Why wrong: FortiGate supports multiple default routes with different distances.
B
Both routes are equal-cost and load-balancing is not working
Why wrong: Routes have different distances, so they are not equal-cost.
C
The configuration is invalid because duplicate default routes are not allowed
Why wrong: Multiple default routes are allowed with different distances.
D
The gateway 203.0.113.1 (port1) is unreachable
The first route is preferred (distance 10), so if its gateway is unreachable, traffic fails.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The gateway 203.0.113.1 (port1) is unreachable
When a FortiGate has multiple default routes, it uses the route with the lowest distance (administrative distance) as the primary route. If the gateway for the primary route (203.0.113.1 on port1) is unreachable, the FortiGate will not be able to reach 8.8.8.8, even if a secondary default route exists. The ping fails because the device cannot ARP for the gateway or the next-hop is down, causing the route to be inactive.
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.
✗
The second route is overwriting the first route
Why it's wrong here
FortiGate supports multiple default routes with different distances.
✗
Both routes are equal-cost and load-balancing is not working
Why it's wrong here
Routes have different distances, so they are not equal-cost.
✗
The configuration is invalid because duplicate default routes are not allowed
Why it's wrong here
Multiple default routes are allowed with different distances.
✓
The gateway 203.0.113.1 (port1) is unreachable
Why this is correct
The first route is preferred (distance 10), so if its gateway is unreachable, traffic fails.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
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 assume both default routes are active and load-balanced, but FortiGate uses administrative distance to select a single active route, and if the gateway of that route is unreachable, the route becomes invalid and no traffic is forwarded until the next route is considered.
Detailed technical explanation
How to think about this question
FortiGate uses the routing table to determine the best path; the route with the lowest administrative distance (e.g., 10 for static) is preferred. If the gateway of the active route becomes unreachable (e.g., due to a down interface or ARP failure), the route is removed from the forwarding table, and the next best route (distance 20) is used. The 'ping' command uses the kernel routing table, so if the primary gateway is unreachable, the ping fails immediately without falling back to the secondary route unless the primary route is fully removed.
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 practitioner preparing for the NSE4 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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: The gateway 203.0.113.1 (port1) is unreachable — When a FortiGate has multiple default routes, it uses the route with the lowest distance (administrative distance) as the primary route. If the gateway for the primary route (203.0.113.1 on port1) is unreachable, the FortiGate will not be able to reach 8.8.8.8, even if a secondary default route exists. The ping fails because the device cannot ARP for the gateway or the next-hop is down, causing the route to be inactive.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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