The correct answer is to deploy a virtual firewall on a vSphere Distributed Switch with a private VLAN. This configuration is essential because a private VLAN (PVLAN) on a VDS isolates east-west traffic between VMs on the same ESXi host and redirects that traffic through the virtual firewall for inspection, all without leaving the hypervisor. On the ENCOR 350-401 exam, this scenario tests your understanding of how to enforce micro-segmentation at the hypervisor layer, often appearing in questions about securing data center traffic flows. A common trap is assuming a standard vSwitch or a physical firewall can inspect intra-host VM traffic efficiently, but those would force traffic off the host, breaking the performance and security model. Remember the key: PVLANs on a VDS create isolated “community” and “isolated” ports, forcing VM-to-VM traffic through the firewall’s promiscuous port. Memory tip: “PVLAN = Path for Virtual Local east-west Analysis Now.”
CCNP Virtualization Practice Question
This 350-401 practice question tests your understanding of virtualization. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
An enterprise uses VMware vSphere to host multiple virtual machines (VMs). The network team wants to implement a virtual firewall on the hypervisor to inspect traffic between VMs on the same ESXi host. Which technology should be used?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy a virtual firewall on a vSphere Distributed Switch with a private VLAN.
Option B is correct because deploying a virtual firewall on a vSphere Distributed Switch (VDS) with a private VLAN (PVLAN) allows the firewall to inspect east-west traffic between VMs on the same ESXi host without sending traffic off the host. The VDS supports PVLANs to isolate VM traffic and redirect it to the virtual firewall for inspection, enabling granular security within the hypervisor.
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.
✗
Use VXLAN to encapsulate traffic and send it to a firewall.
Why it's wrong here
VXLAN is for network virtualization, not for local inspection.
✓
Deploy a virtual firewall on a vSphere Distributed Switch with a private VLAN.
Why this is correct
Private VLAN can redirect traffic to the virtual firewall.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use a vSphere Standard Switch and configure port mirroring.
Why it's wrong here
Port mirroring only copies traffic, does not enforce security.
✗
Deploy a physical firewall and route all VM traffic through it.
Why it's wrong here
Physical firewall would require traffic to leave the host, not inspect intra-host traffic.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between monitoring tools (port mirroring) and inline security appliances (virtual firewalls), leading candidates to mistakenly choose port mirroring for traffic inspection instead of a solution that can actually enforce policies.
Detailed technical explanation
How to think about this question
In a VDS with PVLANs, the primary VLAN (PV) carries traffic to the virtual firewall, while secondary isolated VLANs (IV) or community VLANs (CV) restrict VM-to-VM communication; the firewall acts as a promiscuous port to inspect and filter traffic between isolated VMs. This setup leverages the VDS’s ability to enforce PVLAN rules at the vSwitch level, ensuring that traffic between VMs in different PVLANs is forwarded through the firewall for stateful inspection. In real-world scenarios, this is critical for micro-segmentation in data centers, where VMs in the same subnet must be protected without relying on external firewalls.
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.
Virtualization — This question tests Virtualization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Deploy a virtual firewall on a vSphere Distributed Switch with a private VLAN. — Option B is correct because deploying a virtual firewall on a vSphere Distributed Switch (VDS) with a private VLAN (PVLAN) allows the firewall to inspect east-west traffic between VMs on the same ESXi host without sending traffic off the host. The VDS supports PVLANs to isolate VM traffic and redirect it to the virtual firewall for inspection, enabling granular security within the hypervisor.
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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Question Discussion
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