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.
An administrator is configuring a VLAN interface on a FortiGate. The physical interface is port2 and the VLAN ID is 100. Which of the following correctly creates the VLAN interface?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
config system interface edit port2.100 set vlanid 100 set type vlan next end
Option A is correct because it uses the correct CLI syntax to create a VLAN subinterface on a FortiGate. The command `config system interface` enters the interface configuration context, `edit port2.100` creates or edits the subinterface named with the physical interface and VLAN ID, `set vlanid 100` assigns the VLAN tag, and `set type vlan` explicitly defines the interface type as VLAN. This matches the required configuration for 802.1Q VLAN tagging on FortiGate.
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.
✓
config system interface edit port2.100 set vlanid 100 set type vlan next end
Why this is correct
This is the correct CLI syntax to create a VLAN subinterface with ID 100.
Related concept
Read the scenario before looking for a memorised answer.
✗
config system interface edit port2 set vlanid 100 next end
Why it's wrong here
This attempts to set a VLAN ID on the physical interface itself, which is invalid.
✗
config system interface edit port2.100 set type vlan next end
Why it's wrong here
Missing the 'set vlanid' command; the VLAN ID is required.
✗
config system vlan edit port2.100 set vlanid 100 next end
Why it's wrong here
There is no 'config system vlan' command; VLANs are created under 'config system interface'.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the FortiGate CLI with Cisco IOS, where `interface port2.100` automatically implies a VLAN subinterface without needing an explicit `set type vlan` or `set vlanid` command, leading them to choose Option C or D.
Trap categories for this question
Command / output trap
Missing the 'set vlanid' command; the VLAN ID is required.
Detailed technical explanation
How to think about this question
FortiGate VLAN subinterfaces use the naming convention `<physical_interface>.<vlan_id>` (e.g., port2.100) and require both `set type vlan` and `set vlanid <id>` to function. The VLAN ID must match the 802.1Q tag expected by the upstream switch. A common real-world scenario is trunking multiple VLANs over a single physical port to a switch, where each VLAN subinterface must have a unique VLAN ID and an IP address in the corresponding subnet.
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: config system interface edit port2.100 set vlanid 100 set type vlan next end — Option A is correct because it uses the correct CLI syntax to create a VLAN subinterface on a FortiGate. The command `config system interface` enters the interface configuration context, `edit port2.100` creates or edits the subinterface named with the physical interface and VLAN ID, `set vlanid 100` assigns the VLAN tag, and `set type vlan` explicitly defines the interface type as VLAN. This matches the required configuration for 802.1Q VLAN tagging on FortiGate.
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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