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 administrator configures a VLAN interface on a FortiGate trunk port. The VLAN is allowed on the trunk, but the FortiGate cannot ping the default gateway of that VLAN. Which two items must be verified? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VLAN interface has an IP address in the correct subnet.
Option A is correct because the VLAN interface must have an IP address in the correct subnet to communicate with the default gateway. Without a matching subnet, the FortiGate cannot route ICMP packets to the gateway, even if the VLAN is allowed on the trunk.
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 VLAN interface has an IP address in the correct subnet.
Why this is correct
The IP must match the VLAN's subnet for communication.
Related concept
Read the scenario before looking for a memorised answer.
✗
A firewall policy allows ICMP from the FortiGate to the gateway.
Why it's wrong here
Traffic sourced from the FortiGate itself is not subject to firewall policies by default.
✓
The VLAN interface is administratively up.
Why this is correct
If the interface is down, ping will fail.
Related concept
Read the scenario before looking for a memorised answer.
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 a firewall policy is needed for FortiGate-originated traffic, but local-in policies (not regular policies) control such traffic, and ICMP to the gateway is typically allowed by default unless explicitly blocked.
Detailed technical explanation
How to think about this question
When a FortiGate VLAN interface is created on a trunk port, the interface must be administratively up (no shutdown) and have a correct IP address in the VLAN's subnet. The VLAN ID must match the switch's allowed VLAN list; otherwise, frames are dropped at Layer 2. The FortiGate uses its routing table to send ICMP to the gateway, and if the VLAN interface is down or misconfigured, the route is inactive.
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 help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
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 VLAN interface has an IP address in the correct subnet. — Option A is correct because the VLAN interface must have an IP address in the correct subnet to communicate with the default gateway. Without a matching subnet, the FortiGate cannot route ICMP packets to the gateway, even if the VLAN is allowed on the trunk.
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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