- A
VLAN 1 and VLANs 1002-1005 cannot be deleted.
Correct because these are default VLANs that are automatically created and cannot be removed.
- B
The 'show vlan brief' command only displays VLANs that have been created on the switch.
Correct because it shows only configured VLANs, not all possible VLAN numbers.
- C
The 'switchport access vlan 10' command automatically creates VLAN 10 if it does not exist.
Why wrong: Incorrect because the command assigns the port to VLAN 10, but VLAN 10 must already be created; otherwise the port remains inactive.
- D
The 'no switchport' command on a switch port places it into the default VLAN.
Why wrong: Incorrect because 'no switchport' makes the interface a Layer 3 routed port, removing it from VLAN operation.
- E
Extended VLANs (1006-4094) are stored in the vlan.dat file by default.
Why wrong: Incorrect because extended VLANs are stored in the running configuration, not in vlan.dat, unless VTP version 3 is used.
350-401 VLANs and Trunking Practice Question
This 350-401 practice question tests your understanding of vlans and trunking. 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.
Which two statements about VLAN configuration and verification on a Cisco IOS switch are true? (Choose two.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
VLAN 1 and VLANs 1002-1005 cannot be deleted.
Correct: A is true because VLANs 1 and 1002-1005 are reserved (default) and cannot be deleted. B is true because 'show vlan brief' displays only VLANs that exist in the VLAN database, not all possible VLANs. C is incorrect because the 'switchport access vlan' command assigns a port to a VLAN, but the VLAN must already exist or be created first; the command does not automatically create the VLAN. D is incorrect because 'no switchport' converts the interface to a Layer 3 routed port, which does not participate in VLANs. E is incorrect because the extended VLAN range (1006-4094) is not saved in vlan.dat by default; they are stored in the running configuration.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
VLAN 1 and VLANs 1002-1005 cannot be deleted.
Why this is correct
Correct because these are default VLANs that are automatically created and cannot be removed.
Related concept
Access ports place end devices into a single VLAN.
- ✓
The 'show vlan brief' command only displays VLANs that have been created on the switch.
- ✗
The 'switchport access vlan 10' command automatically creates VLAN 10 if it does not exist.
Why it's wrong here
Incorrect because the command assigns the port to VLAN 10, but VLAN 10 must already be created; otherwise the port remains inactive.
- ✗
The 'no switchport' command on a switch port places it into the default VLAN.
Why it's wrong here
Incorrect because 'no switchport' makes the interface a Layer 3 routed port, removing it from VLAN operation.
- ✗
Extended VLANs (1006-4094) are stored in the vlan.dat file by default.
Why it's wrong here
Incorrect because extended VLANs are stored in the running configuration, not in vlan.dat, unless VTP version 3 is used.
Common exam traps
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Trap categories for this question
Command / output trap
Incorrect because the command assigns the port to VLAN 10, but VLAN 10 must already be created; otherwise the port remains inactive.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
- Access ports place end devices into a single VLAN.
- Trunk ports carry multiple VLANs between switches.
- Allowed VLAN lists decide which VLANs can cross a trunk.
- Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
- Use show vlan brief to verify access VLANs.
- Use show interfaces trunk to verify trunk state and allowed VLANs.
- Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
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.
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-401 questions on switching, trunking, and access-port configuration.
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FAQ
Questions learners often ask
What does this 350-401 question test?
VLANs and Trunking — This question tests VLANs and Trunking — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: VLAN 1 and VLANs 1002-1005 cannot be deleted. — Correct: A is true because VLANs 1 and 1002-1005 are reserved (default) and cannot be deleted. B is true because 'show vlan brief' displays only VLANs that exist in the VLAN database, not all possible VLANs. C is incorrect because the 'switchport access vlan' command assigns a port to a VLAN, but the VLAN must already exist or be created first; the command does not automatically create the VLAN. D is incorrect because 'no switchport' converts the interface to a Layer 3 routed port, which does not participate in VLANs. E is incorrect because the extended VLAN range (1006-4094) is not saved in vlan.dat by default; they are stored in the running configuration.
What should I do if I get this 350-401 question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-401 questions on switching, trunking, and access-port configuration.
What is the key concept behind this question?
Access ports place end devices into a single VLAN.
About these practice questions
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Last reviewed: Jun 18, 2026
This 350-401 practice question is part of Courseiva's free Cisco 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 350-401 exam.
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