Question 218 of 521
Configure and Manage vSphere NetworkinghardMultiple ChoiceObjective-mapped

MTU Mismatch

This VCP-DCV practice question tests your understanding of configure and manage vsphere networking. 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.

Exhibit

esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0          128         5           128               1500    vmnic0
VLAN ID: 0
DVS Name         Num Ports   Used Ports  Configured Ports  MTU     Uplinks
DSwitch          256         12          256               9000    vmnic1, vmnic2
  DVPortgroup: Management (VLAN 100, ports: 3)
  DVPortgroup: Production (VLAN 200, ports: 5)
  DVPortgroup: Storage (VLAN 300, ports: 4)

vmkping -I vmk0 192.168.100.1
PING 192.168.100.1 (192.168.100.1): 56 data bytes
64 bytes from 192.168.100.1: icmp_seq=0 ttl=64 time=0.345 ms
--- 192.168.100.1 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss

Refer to the exhibit. An administrator notices that virtual machines on the Production port group are unable to communicate with hosts on VLAN 200. The Management and Storage port groups work fine. What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Exhibit

esxcfg-vswitch -l
Switch Name      Num Ports   Used Ports  Configured Ports  MTU     Uplinks
vSwitch0          128         5           128               1500    vmnic0
VLAN ID: 0
DVS Name         Num Ports   Used Ports  Configured Ports  MTU     Uplinks
DSwitch          256         12          256               9000    vmnic1, vmnic2
  DVPortgroup: Management (VLAN 100, ports: 3)
  DVPortgroup: Production (VLAN 200, ports: 5)
  DVPortgroup: Storage (VLAN 300, ports: 4)

vmkping -I vmk0 192.168.100.1
PING 192.168.100.1 (192.168.100.1): 56 data bytes
64 bytes from 192.168.100.1: icmp_seq=0 ttl=64 time=0.345 ms
--- 192.168.100.1 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss

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 MTU setting on the DSwitch (9000) is incompatible with the physical network for VLAN 200.

The exhibit shows that the DVS has MTU 9000 configured, but the Production port group inherits this MTU. If the physical network infrastructure does not support jumbo frames (MTU >1500), traffic on VLAN 200 may be dropped due to fragmentation issues. The Management port group is on VLAN 100 and Storage on VLAN 300, which might be configured differently or not experiencing the issue yet. The correct answer is that the MTU mismatch causes the Production traffic to fail.

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.

  • The uplinks for DSwitch are not properly configured for VLAN 200.

    Why it's wrong here

    The uplinks vmnic1 and vmnic2 are connected to the DSwitch, and VLAN 200 is set on the port group. The issue is not uplink configuration.

  • The MTU setting on the DSwitch (9000) is incompatible with the physical network for VLAN 200.

    Why this is correct

    Jumbo frames (MTU 9000) require end-to-end support. If the physical switches do not support jumbo frames on VLAN 200, packets larger than 1500 bytes are dropped.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Access ports place end devices into a single VLAN.

  • The Production port group is not attached to any uplink.

    Why it's wrong here

    The DSwitch has uplinks vmnic1 and vmnic2, and the port group is part of the DSwitch, so it uses those uplinks.

  • There is a VLAN ID mismatch between the virtual switch and physical switch for VLAN 200.

    Why it's wrong here

    The VLAN ID is set to 200 on the port group, which should match the physical switch configuration. The exhibit does not indicate a mismatch.

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.

Visual reference

Switch VLAN 10 Sales (192.168.10.0/24) PC-A PC-B VLAN 20 HR (192.168.20.0/24) PC-C PC-D Router VLANs isolate traffic — inter-VLAN routing requires a Layer 3 device

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 VCP-DCV questions on switching, trunking, and access-port configuration.

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Related VCP-DCV practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

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FAQ

Questions learners often ask

What does this VCP-DCV question test?

Configure and Manage vSphere Networking — This question tests Configure and Manage vSphere Networking — Access ports place end devices into a single VLAN..

What is the correct answer to this question?

The correct answer is: The MTU setting on the DSwitch (9000) is incompatible with the physical network for VLAN 200. — The exhibit shows that the DVS has MTU 9000 configured, but the Production port group inherits this MTU. If the physical network infrastructure does not support jumbo frames (MTU >1500), traffic on VLAN 200 may be dropped due to fragmentation issues. The Management port group is on VLAN 100 and Storage on VLAN 300, which might be configured differently or not experiencing the issue yet. The correct answer is that the MTU mismatch causes the Production traffic to fail.

What should I do if I get this VCP-DCV 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 VCP-DCV questions on switching, trunking, and access-port configuration.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Access ports place end devices into a single VLAN.

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Last reviewed: Jul 4, 2026

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This VCP-DCV practice question is part of Courseiva's free VMware 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 VCP-DCV exam.