Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A user-facing switchport should carry traffic for only one VLAN and should not attempt DTP trunk negotiation. Which two-command approach best fits that design?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
`switchport mode access` and `switchport access vlan 20`
This is correct because it explicitly makes the port an access port in VLAN 20.
B
Distractor review
`switchport mode trunk` and `switchport trunk native vlan 20`
This is wrong because it makes the interface a trunk rather than a host-facing access port.
C
Distractor review
`switchport mode dynamic desirable` and `switchport trunk allowed vlan 20`
This is wrong because it still relies on trunk negotiation behavior.
D
Distractor review
`no switchport` and `ip address 20.20.20.1 255.255.255.0`
This is wrong because it converts the interface to Layer 3 routed-port behavior on supported devices.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting options that enable dynamic trunk negotiation, such as 'switchport mode dynamic desirable,' because they appear to allow VLAN assignment flexibility. However, these modes cause the port to attempt trunk negotiation via DTP, which is unsuitable for user-facing ports that should carry only one VLAN. Another trap is configuring the port as a trunk with a native VLAN, which exposes the port to multiple VLANs and potential VLAN hopping attacks. Lastly, using 'no switchport' converts the interface to a routed port, removing VLAN functionality entirely, which contradicts the requirement for a single VLAN access port.
Technical deep dive
How to think about this question
In Cisco switches, switchports can operate in different modes: access, trunk, or dynamic. An access port carries traffic for a single VLAN and is typically used to connect end devices such as PCs, printers, or IP phones. Trunk ports carry traffic for multiple VLANs simultaneously, tagging frames with VLAN identifiers. Dynamic Trunking Protocol (DTP) is a Cisco proprietary protocol that negotiates trunk links between switches automatically, which can be enabled or disabled depending on the port configuration. The command 'switchport mode access' explicitly configures the interface as an access port, disabling DTP and preventing the port from negotiating a trunk link. This ensures the port only forwards untagged frames belonging to the assigned VLAN. The 'switchport access vlan 20' command assigns VLAN 20 as the access VLAN, so all untagged traffic arriving on that port is associated with VLAN 20. This combination is the recommended approach for user-facing ports to maintain VLAN segmentation and avoid unintended trunking. A common exam trap is confusing access ports with trunk ports or relying on dynamic trunk negotiation modes such as 'dynamic desirable' or 'dynamic auto.' These modes allow the port to negotiate trunking, which is inappropriate for user-facing endpoints and can cause VLAN leakage or security issues. Additionally, using 'no switchport' converts the interface to Layer 3 mode, removing VLAN membership entirely, which is not suitable for typical access ports. Understanding these distinctions helps avoid misconfigurations and aligns with best practices for enterprise network design.
KKey Concepts to Remember
- A user-facing switchport configured as an access port carries traffic for only one VLAN and does not participate in VLAN trunking protocol (DTP) negotiation.
- The command 'switchport mode access' forces the interface into access mode, disabling dynamic trunk negotiation and preventing the port from becoming a trunk.
- The command 'switchport access vlan <vlan-id>' assigns the specific VLAN that the access port will carry untagged traffic for, ensuring proper VLAN segmentation.
- Dynamic Trunking Protocol (DTP) enables switches to negotiate trunk links automatically, but it should be disabled on user-facing ports to avoid unintended trunk formation.
- Configuring a port as a trunk or using dynamic desirable mode causes the port to attempt trunk negotiation, which is inappropriate for host-facing endpoints.
- The 'no switchport' command converts a Layer 2 interface into a Layer 3 routed port, which is not suitable for user-facing access ports that require VLAN membership.
- Explicitly setting a port to access mode and assigning an access VLAN is the standard best practice for edge ports connecting end devices in enterprise networks.
- Misconfiguring user-facing ports as trunks or enabling DTP can lead to security risks, VLAN hopping, and network instability due to unintended VLAN traffic.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
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Question 2
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Question 3
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Question 4
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Question 5
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Question 6
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FAQ
Questions learners often ask
What does this 200-301 question test?
A user-facing switchport configured as an access port carries traffic for only one VLAN and does not participate in VLAN trunking protocol (DTP) negotiation.
What is the correct answer to this question?
The correct answer is: `switchport mode access` and `switchport access vlan 20` — The best fit is to set the interface to access mode and assign the access VLAN. In plain language, a user-facing endpoint such as a PC should not behave like a trunk. By explicitly configuring access mode, the switch stops relying on negotiation and treats the interface as a one-VLAN host port. The access VLAN command then tells the switch which VLAN that port belongs to. This is the standard edge-port design in most enterprise networks. The correct answer is the one that combines an explicit access role with a specific VLAN assignment.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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