- A
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.
This is correct because it creates the required VLAN, assigns the access ports to VLAN 10, and properly configures the trunk with 802.1Q encapsulation and native VLAN 99, which ensures the PCs are in the correct VLAN and the trunk is secure.
- B
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation isl and native VLAN 99.
Why wrong: This is incorrect because ISL encapsulation is not supported on modern Cisco switches; 802.1Q is the standard. Using ISL would cause the trunk to fail or not form.
- C
Create VLAN 10, assign G0/1 and G0/2 as trunk ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.
Why wrong: This is incorrect because access ports should not be configured as trunk ports. Trunk ports carry multiple VLANs, while access ports belong to a single VLAN. Assigning G0/1 and G0/2 as trunk ports would allow them to carry multiple VLANs, which is not desired for PCs.
- D
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 1.
Why wrong: This is incorrect because the native VLAN on the trunk should be changed to 99 as specified in the question. Leaving native VLAN as 1 is a security risk and does not meet the requirement.
Quick Answer
The correct answer is to create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, and configure G0/3 as a trunk with 802.1Q encapsulation and native VLAN 99. This configuration is necessary because access ports must be explicitly set to switchport mode access before being assigned to a VLAN, ensuring the PCs are placed in the correct broadcast domain for communication. The trunk link requires explicit dot1q encapsulation on older switches, and changing the native VLAN from the default VLAN 1 to VLAN 99 is a security best practice to prevent VLAN hopping and maintain consistency across the trunk. On the CCNA 200-301 v2 exam, this scenario tests your understanding of VLAN creation, access port assignment, and trunk configuration with native VLAN modification—a common trap is forgetting to set the trunk encapsulation or assuming the native VLAN can remain as VLAN 1. A helpful memory tip is "Create, Access, Trunk, Native" (CATN): create the VLAN, set access mode, configure trunk, and specify the native VLAN.
CCNA Switching and Network Access Practice Question
This 200-301 practice question tests your understanding of switching and network access. 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.
You are connected to SW1 via the console. SW1 is a Layer 2 switch. Ports G0/1 and G0/2 are connected to two PCs that should be in VLAN 10 (Sales). Port G0/3 is a trunk link to another switch. The PCs are currently unable to communicate because the ports are in VLAN 1. Configure the switch to place the ports in the correct VLAN and ensure the trunk is properly configured with 802.1Q encapsulation and native VLAN 99.
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
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.
VLAN 10 must be created and the access ports must be explicitly set to access mode with 'switchport mode access' before assigning them to VLAN 10. Assigning the access ports to VLAN 10 places the PCs in the correct broadcast domain. The trunk needed explicit 802.1Q encapsulation and a native VLAN change to 99 for security and consistency.
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.
- ✓
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.
Why this is correct
This is correct because it creates the required VLAN, assigns the access ports to VLAN 10, and properly configures the trunk with 802.1Q encapsulation and native VLAN 99, which ensures the PCs are in the correct VLAN and the trunk is secure.
Related concept
Access ports place end devices into a single VLAN.
- ✗
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation isl and native VLAN 99.
Why it's wrong here
This is incorrect because ISL encapsulation is not supported on modern Cisco switches; 802.1Q is the standard. Using ISL would cause the trunk to fail or not form.
- ✗
Create VLAN 10, assign G0/1 and G0/2 as trunk ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.
- ✗
Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 1.
Why it's wrong here
This is incorrect because the native VLAN on the trunk should be changed to 99 as specified in the question. Leaving native VLAN as 1 is a security risk and does not meet the requirement.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.Correct answer▾
Why this is correct
This is correct because it creates the required VLAN, assigns the access ports to VLAN 10, and properly configures the trunk with 802.1Q encapsulation and native VLAN 99, which ensures the PCs are in the correct VLAN and the trunk is secure.
✗Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation isl and native VLAN 99.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that ISL is a legacy Cisco proprietary trunking protocol, and modern switches default to 802.1Q. The question specifies 802.1Q encapsulation.
Why candidates choose this
Candidates might pick this because they remember ISL as a trunking protocol and think it is still widely used, or they confuse it with 802.1Q.
✗Create VLAN 10, assign G0/1 and G0/2 as trunk ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that ports connected to end devices (PCs) should be access ports, not trunk ports. Trunk ports are used for inter-switch links.
Why candidates choose this
Candidates might pick this because they think trunk ports can be used for any connection, or they confuse the concept of trunking with VLAN assignment.
✗Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 1.Wrong answer — click to see why▾
Why this is wrong here
The specific factual error is that the native VLAN must be explicitly set to 99. Native VLAN 1 is the default and is often targeted in VLAN hopping attacks.
Why candidates choose this
Candidates might pick this because they know native VLAN 1 is the default and think it is acceptable, or they forget to change it as per the requirement.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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.
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 200-301 questions on switching, trunking, and access-port configuration.
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FAQ
Questions learners often ask
What does this 200-301 question test?
Switching and Network Access — This question tests Switching and Network Access — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: Create VLAN 10, assign G0/1 and G0/2 as access ports in VLAN 10, configure G0/3 as trunk with encapsulation dot1q and native VLAN 99. — VLAN 10 must be created and the access ports must be explicitly set to access mode with 'switchport mode access' before assigning them to VLAN 10. Assigning the access ports to VLAN 10 places the PCs in the correct broadcast domain. The trunk needed explicit 802.1Q encapsulation and a native VLAN change to 99 for security and consistency.
What should I do if I get this 200-301 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 200-301 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
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
3 more ways this is tested on 200-301
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You are connected to SW1 via console. SW1 is a Layer 2 switch with two ports (G0/1 and G0/2) connected to a host. The host should be able to send and receive traffic on VLAN 10 and VLAN 20. Configure the two ports as a trunk link to the host, but ensure that the trunk only carries VLANs 10 and 20, and set the native VLAN to VLAN 99.
medium- ✓ A.interface range gigabitethernet0/1-2 switchport mode trunk switchport trunk allowed vlan 10,20 switchport trunk native vlan 99
- B.interface range gigabitethernet0/1-2 switchport mode trunk switchport trunk allowed vlan 10-20 switchport trunk native vlan 99
- C.interface range gigabitethernet0/1-2 switchport mode trunk switchport trunk allowed vlan 10,20 switchport native vlan 99
- D.interface range gigabitethernet0/1-2 switchport mode trunk switchport trunk allowed vlan 10,20 switchport trunk native vlan 1
Why A: Configuring the ports as trunks allows multiple VLANs. The 'allowed vlan' command restricts the trunk to only VLANs 10 and 20, while 'native vlan 99' sets the untagged VLAN to 99, ensuring proper tagging and avoiding VLAN mismatch.
Variation 2. You are connected to SW1 via the console. SW1 is a Layer 2 switch connected to router R1 via trunk link G0/1. R1 performs inter-VLAN routing using subinterfaces. VLANs 10, 20, and 30 exist on SW1. Hosts in VLAN 10 (192.168.10.0/24) can ping R1's subinterface, but cannot communicate with hosts in VLAN 20. You suspect the trunk is not allowing VLAN 20 traffic.
medium- ✓ A.Configure 'switchport trunk allowed vlan add 20' on SW1's G0/1 interface.
- B.Configure 'switchport mode access' on SW1's G0/1 interface.
- C.Configure 'switchport trunk native vlan 20' on SW1's G0/1 interface.
- D.Configure 'switchport trunk allowed vlan except 20' on SW1's G0/1 interface.
Why A: Trunks carry traffic for multiple VLANs. The 'switchport trunk allowed vlan' command restricts which VLANs are permitted. Initially, VLAN 20 was not in the allowed list, so traffic was dropped. Adding VLAN 20 to the allowed list resolves the issue.
Variation 3. You are connected to SW1 via the console. SW1 is a Layer 2 switch connected to router R1 via trunk port G0/1. The trunk is currently using VLAN 1 as native VLAN, but the network administrator wants to change the native VLAN to VLAN 99 for security. Configure the trunk on G0/1 to use native VLAN 99 and verify.
medium- ✓ A.SW1(config)# interface g0/1 SW1(config-if)# switchport trunk native vlan 99 SW1(config-if)# end SW1# show interfaces trunk
- B.SW1(config)# interface g0/1 SW1(config-if)# switchport trunk allowed vlan 99 SW1(config-if)# end SW1# show vlan brief
- C.SW1(config)# vlan 99 SW1(config-vlan)# name Native SW1(config-vlan)# exit SW1(config)# interface g0/1 SW1(config-if)# switchport mode trunk SW1(config-if)# switchport trunk native vlan 99 SW1(config-if)# end SW1# show interfaces trunk
- D.SW1(config)# interface g0/1 SW1(config-if)# switchport trunk native vlan 99 SW1(config-if)# end SW1# show vlan id 99
Why A: Changing the native VLAN on a trunk prevents VLAN hopping attacks. The native VLAN carries untagged traffic; here it is changed from default VLAN 1 to VLAN 99.
Last reviewed: Jun 7, 2026
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