The answer is that VLANs 2-9 are allowed but not active on the trunk. This conclusion is drawn directly from comparing the “Vlans allowed on trunk” section, which lists VLANs 1-1005, against the “Vlans allowed and active in management domain” section, which shows only VLANs 1, 10, and 20. The technical concept here is that a trunk can be configured to permit a wide range of VLANs, but traffic will only forward for those VLANs that are both allowed and active—meaning the VLAN must exist in the switch’s VLAN database and have at least one active port in that VLAN. On the ENCOR 350-401 exam, this output interpretation tests your ability to distinguish between allowed, active, and forwarding states, a common trap being that candidates assume all allowed VLANs are forwarding. A reliable memory tip is “Allowed is the door, active is the key”—the trunk permits the VLANs, but only active ones can actually pass traffic.
350-401 VLANs and Trunking Practice Question
This 350-401 practice question tests your understanding of vlans and trunking. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
A network engineer runs the following command on Switch SW1:
SW1# show interfaces trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Gi0/2 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 1-1005
Gi0/2 1-1005
Port Vlans allowed and active in management domain
Gi0/1 1,10,20
Gi0/2 1,10,20
Port Vlans in spanning tree forwarding state and not pruned
Gi0/1 1,10,20
Gi0/2 1,10,20
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
VLANs 2-9 are allowed but not active on the trunk.
The output shows that VLANs 1-1005 are allowed on the trunk, but only VLANs 1, 10, and 20 are listed as active in the management domain. This means VLANs 2-9 are configured on the trunk but are not active (i.e., not created or not present on the switch), so they do not forward traffic. Option A correctly identifies this condition.
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.
✓
VLANs 2-9 are allowed but not active on the trunk.
Why this is correct
The 'allowed' list includes 1-1005, but only VLANs 1,10,20 are active; thus VLANs 2-9 are allowed but not active (not created in VLAN database).
Related concept
Read the scenario before looking for a memorised answer.
✗
The trunk is using ISL encapsulation.
Why it's wrong here
The encapsulation is shown as 802.1q.
✗
VLAN 1 is pruned from the trunk.
Why it's wrong here
VLAN 1 is in the forwarding state, so it is not pruned.
Common exam trap: answer the scenario, not the keyword
Cisco often tests the difference between 'allowed on trunk' and 'active in management domain' to trick candidates into thinking all allowed VLANs are forwarding, when in fact only active VLANs forward traffic.
Trap categories for this question
Command / output trap
The encapsulation is shown as 802.1q.
Detailed technical explanation
How to think about this question
The 'Vlans allowed and active in management domain' field reflects only VLANs that exist in the VLAN database and are not shutdown, while the 'Vlans allowed on trunk' field shows the configured allowed list. This distinction is critical for troubleshooting: a VLAN may be allowed but inactive, causing traffic to be dropped. In real-world scenarios, this often occurs when a VLAN is created on one switch but not propagated via VTP or manually added to another switch, leading to connectivity gaps.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 350-401 question in full detail.
VLANs and Trunking — This question tests VLANs and Trunking — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: VLANs 2-9 are allowed but not active on the trunk. — The output shows that VLANs 1-1005 are allowed on the trunk, but only VLANs 1, 10, and 20 are listed as active in the management domain. This means VLANs 2-9 are configured on the trunk but are not active (i.e., not created or not present on the switch), so they do not forward traffic. Option A correctly identifies this condition.
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.
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 →
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. A network engineer runs the following command on Switch SW1:
SW1# show interfaces gi0/1 trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 desirable n-802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 1-1005
Port Vlans allowed and active in management domain
Gi0/1 1,10,20
Port Vlans in spanning tree forwarding state and not pruned
Gi0/1 1,10,20
Based on this output, what can be concluded?
medium
A.The interface is configured as an access port.
B.The trunk is using ISL encapsulation.
✓ C.VLANs 2-9 are allowed but not active.
D.The native VLAN is 10.
Why C: The output shows that VLANs 1-1005 are allowed on the trunk, but only VLANs 1, 10, and 20 are active in the management domain. This means VLANs 2-9 and 11-19, 21-1005 are allowed but not active (i.e., not created or not present on the switch). Option C correctly identifies that VLANs 2-9 are among those allowed but not active.
Variation 2. A network engineer runs the following command on Switch SW1:
SW1# show interfaces gi0/1 trunk
Port Mode Encapsulation Status Native vlan
Gi0/1 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/1 10,20
Port Vlans allowed and active in management domain
Gi0/1 10,20
Port Vlans in spanning tree forwarding state and not pruned
Gi0/1 10,20
Based on this output, what can be concluded?
hard
A.VLAN 1 is allowed on this trunk.
B.The trunk is using DTP dynamic desirable mode.
✓ C.Only VLANs 10 and 20 are allowed on this trunk.
D.The native VLAN is 10.
Why C: The output shows that the 'Vlans allowed on trunk' list contains only VLANs 10 and 20. This means the trunk has been explicitly configured to permit only those VLANs, and all other VLANs (including VLAN 1) are pruned or blocked from traversing the trunk. Therefore, only VLANs 10 and 20 are allowed, making option C correct.
Last reviewed: Jun 24, 2026
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