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Question 836 of 2,015
Enterprise Network Design →mediumMultiple ChoiceObjective-mapped

Quick Answer

The correct answer is that the trunk will only allow VLANs 10, 20, and 30, with VLAN 10 configured as the native VLAN. This is because the `switchport trunk allowed vlan 10,20,30` command explicitly prunes all other VLANs from the trunk, while the `switchport trunk native vlan 10` command designates VLAN 10 to carry untagged frames. Importantly, the native VLAN can still be included in the allowed list and can have a functional switched virtual interface (SVI), as shown by the `interface Vlan10` configuration, which will come up as long as the trunk port is active. On the ENCOR 350-401 exam, this scenario tests your understanding that the native VLAN is not automatically excluded from the allowed VLAN list—a common trap is assuming the native VLAN is handled separately or that an SVI requires an access port. A reliable memory tip: the native VLAN is just a VLAN that happens to be untagged; it still obeys all allowed VLAN rules, so “native is not special” when it comes to the allowed list.

350-401 Enterprise Network Design Practice Question

This 350-401 practice question tests your understanding of enterprise network design. 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.

Consider this configuration:

interface GigabitEthernet0/2
 switchport mode trunk
 switchport trunk native vlan 10
 switchport trunk allowed vlan 10,20,30

!

interface Vlan10
 ip address 192.168.10.1 255.255.255.0

Which statement is true about this configuration?

Question 1mediummultiple choice
Open the full VLAN trunking answer →

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

✓

The trunk will only allow VLANs 10, 20, and 30, and VLAN 10 is the native VLAN.

Option B is correct because the configuration explicitly permits VLANs 10, 20, and 30 on the trunk using the 'switchport trunk allowed vlan' command, and VLAN 10 is set as the native VLAN with the 'switchport trunk native vlan 10' command. The native VLAN carries untagged traffic on the trunk, but it is still a valid VLAN that can be included in the allowed list and can have an SVI for routing. The SVI for VLAN 10 will come up as long as the VLAN exists and there is at least one active switchport in that VLAN, which is satisfied by the trunk port.

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 native VLAN 10 cannot be used as a routed interface because it is the native VLAN.

    Why it's wrong here

    There is no restriction preventing the native VLAN from being used as an SVI; it is a common practice.

  • ✓

    The trunk will only allow VLANs 10, 20, and 30, and VLAN 10 is the native VLAN.

    Why this is correct

    The 'allowed vlan' command restricts the trunk to VLANs 10, 20, and 30, and 'native vlan 10' sets VLAN 10 as the native VLAN.

    Related concept

    Read the scenario before looking for a memorised answer.

  • ✗

    The SVI for VLAN 10 will not come up because the native VLAN must be untagged.

    Why it's wrong here

    The SVI can come up regardless of native VLAN status; the native VLAN is simply untagged on the trunk.

  • ✗

    The configuration is invalid because the native VLAN must be the same as the management VLAN.

    Why it's wrong here

    There is no such requirement; the native VLAN can be any VLAN.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Cisco often tests the misconception that the native VLAN cannot be used for routing or that it must be excluded from the allowed VLAN list, but in reality, the native VLAN is simply the VLAN that carries untagged frames and can be included in the allowed list and have an SVI.

Detailed technical explanation

How to think about this question

On a trunk port, the native VLAN (default VLAN 1) is used for untagged frames, but it can be changed to any VLAN; the 'switchport trunk native vlan' command does not remove the VLAN from the allowed list, so VLAN 10 remains both native and allowed. The SVI (Switch Virtual Interface) for VLAN 10 will be operational as long as the VLAN is active in the VLAN database and there is at least one switchport (access or trunk) in that VLAN; the trunk port provides that connectivity. In real-world scenarios, using a non-default native VLAN (e.g., VLAN 10) is a common security practice to avoid VLAN hopping attacks, and the SVI can still route traffic for that VLAN.

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.

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FAQ

Questions learners often ask

What does this 350-401 question test?

Enterprise Network Design — This question tests Enterprise Network Design — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The trunk will only allow VLANs 10, 20, and 30, and VLAN 10 is the native VLAN. — Option B is correct because the configuration explicitly permits VLANs 10, 20, and 30 on the trunk using the 'switchport trunk allowed vlan' command, and VLAN 10 is set as the native VLAN with the 'switchport trunk native vlan 10' command. The native VLAN carries untagged traffic on the trunk, but it is still a valid VLAN that can be included in the allowed list and can have an SVI for routing. The SVI for VLAN 10 will come up as long as the VLAN exists and there is at least one active switchport in that VLAN, which is satisfied by the trunk port.

What should I do if I get this 350-401 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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Last reviewed: Jun 24, 2026

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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.