VCP-DCV Configure and Manage vSphere Networking Practice Test 4 — 15 Questions

Question 1

A vSphere administrator is troubleshooting connectivity issues for a virtual machine that is unable to communicate with other VMs on the same VLAN. The VM is connected to a distributed port group on a vSphere Distributed Switch (vDS). The administrator verifies that the VM's IP configuration is correct and that the port group is configured with the correct VLAN ID. However, the VM can only communicate with other VMs on the same ESXi host. What is the most likely cause?

Accepted Answer

The physical switch ports connecting the ESXi hosts are not configured as trunk ports for the VLAN.. Option C is correct because if VMs on the same VLAN cannot communicate across hosts, the physical switch ports connecting ESXi hosts are likely not configured as trunk ports for that VLAN. This prevents VLAN-tagged frames from passing between hosts. Option A is incorrect because VLAN trunking policy on the vDS is not required for basic VLAN communication; the port group VLAN ID handles tagging. Option B is incorrect because the MAC address is automatically assigned and would not cause host-only communication. Option D is incorrect because the 'forging transmits' security policy controls MAC address changes, not basic connectivity.

Answer

The vDS is not configured with a VLAN trunking policy.

Answer

The VM's network adapter is configured with the wrong MAC address.

Answer

The distributed port group has forging transmits set to reject.

Question 2

An administrator needs to configure a vSphere Standard Switch (vSS) for a small environment. Which component must be created first before adding a virtual machine to the network?

Accepted Answer

Create a standard switch.. Option A is correct because a standard switch must exist to create port groups. Without the switch, port groups cannot be created. Option B is incorrect because the uplink is part of the switch creation. Option C is incorrect because a VM port group is created after the switch. Option D is incorrect because the VMkernel interface is for management/storage, not for regular VM connectivity.

Answer

Configure a VMkernel interface.

Answer

Create a virtual machine port group.

Answer

Add a physical uplink to the host.

Question 3

A vSphere environment uses a vSphere Distributed Switch (vDS) with 10G uplinks and Network I/O Control (NIOC) enabled. Administrators report that during peak traffic, NFS storage traffic is experiencing high latency, while other traffic types remain unaffected. The vDS has default NIOC shares and limits. Which action should be taken to prioritize NFS traffic without completely starving other traffic?

Accepted Answer

Increase the shares for the NFS traffic class.. Option D is correct because increasing the shares for the NFS system traffic class gives it a higher proportion of bandwidth during contention, without imposing a hard limit. Option A is incorrect because setting a high limit for NFS could starve other traffic if NFS uses all bandwidth. Option B is incorrect because setting a low limit for NFS would cap NFS traffic, worsening performance. Option C is incorrect because disabling NIOC removes all prioritization, making all traffic equal and not solving the issue.

Answer

Set a low bandwidth limit for the NFS traffic class.

Answer

Set a high bandwidth reservation for the NFS traffic class.

Answer

Disable Network I/O Control on the vDS.

Question 4

An organization has deployed a vSphere Distributed Switch (vDS) across multiple ESXi hosts. The security team requires that no virtual machine can change its MAC address to impersonate another device. Which security policy setting on the distributed port group should be configured to fulfill this requirement?

Accepted Answer

Set 'Forged transmits' to 'Reject'.. Option B is correct because the 'Forged transmits' policy, when set to 'Reject', drops any outbound frames with a source MAC address different from the one assigned to the virtual NIC. This prevents MAC impersonation. Option A is incorrect because 'Promiscuous mode' allows the VM to see all traffic on the port, which is a security risk and unrelated to MAC impersonation. Option C is incorrect because 'MAC address changes' controls whether the VM can change its effective MAC address, but the question is about outward impersonation. Option D is incorrect because traffic shaping limits bandwidth, not MAC security.

Answer

Set 'MAC address changes' to 'Reject'.

Answer

Set 'Promiscuous mode' to 'Reject'.

Answer

Enable traffic shaping and set a low average bandwidth.

Question 5

A vSphere administrator needs to provide redundancy for VM traffic on a vSphere Standard Switch by using multiple physical uplinks. Which teaming configuration should be used to ensure that if one uplink fails, traffic automatically fails over to another?

Accepted Answer

Set load balancing to 'Route based on originating virtual port' and make one uplink active and one standby.. Option A is correct because 'Route based on originating virtual port' with active/standby failover ensures one uplink is active and the other is standby, with automatic failover. Option B is incorrect because load balancing distributes traffic but doesn't inherently imply failover; however, active/active can also fail over, but the question asks for failover specifically. Option C is incorrect because 'Explicit failover order' is a method, not a load balancing policy. Option D is incorrect because uplink failure detection is a setting, not a policy.

Answer

Set load balancing to 'Route based on IP hash' and make both uplinks active.

Answer

Enable 'Use explicit failover order' and configure 'Network failures' detection.

Answer

Set load balancing to 'Explicit failover order' and set one uplink as active.

Question 6

A vSphere administrator is configuring Network I/O Control (NIOC) on a vSphere Distributed Switch to prioritize vMotion traffic during maintenance windows. The environment has three system traffic classes: Management, NFS, and vMotion. The administrator wants to ensure that when the network is congested, vMotion gets at least 50% of the available bandwidth, while Management and NFS each get at least 25%. Which NIOC configuration achieves this?

Accepted Answer

Set the vMotion traffic class shares to 50, Management shares to 25, and NFS shares to 25.. Option A is correct because shares allocate bandwidth proportionally during contention. Setting shares to 50/25/25 gives vMotion 50% of the bandwidth when all are busy. Option B is incorrect because reservations guarantee minimum bandwidth but do not guarantee proportional allocation; plus, the question asks for 'at least' percentages during congestion, which shares handle. Option C is incorrect because limits cap bandwidth and would prevent vMotion from using more than 500 Mbps, not guaranteeing 50% of available bandwidth. Option D is incorrect because disabling NIOC removes prioritization, making all traffic equal.

Answer

Set a limit of 500 Mbps for Management and NFS, and no limit for vMotion.

Answer

Set a reservation of 500 Mbps for vMotion, 250 Mbps for Management, and 250 Mbps for NFS.

Answer

Do nothing; NIOC is not needed because all traffic types are equally important.

Question 7

An administrator is troubleshooting an issue where a VM on a vSphere Distributed Switch cannot receive traffic from outside its subnet. The VM can send traffic out and receive replies from hosts on the same subnet. The default gateway is configured correctly. What is the most likely cause?

Accepted Answer

The router does not have a route back to the VM's subnet.. Option B is correct because if the route is missing on the physical router back to the VM's subnet, the router drops return traffic. This is a common routing misconfiguration. Option A is incorrect because the default gateway is the VM's gateway; the ESXi host's management gateway is unrelated. Option C is incorrect because the VTEP IP is for VXLAN, not regular routing. Option D is incorrect because a port group VLAN mismatch would cause issues with same-subnet communication as well.

Answer

The VXLAN Tunnel Endpoint (VTEP) IP is not reachable from the remote subnet.

Answer

The ESXi host's default gateway is misconfigured.

Answer

The port group VLAN ID is different from the physical switch trunk allowed VLAN.

Question 8

A virtual machine is configured with two vNICs connected to different standard port groups (VLAN 10 and VLAN 20). The administrator wants to use both vNICs for load balancing and failover within the VM OS. Which condition must be met on the vSwitch side?

Accepted Answer

Configure NIC teaming within the guest operating system.. Option C is correct because the VM OS must have NIC teaming configured to use both interfaces. The vSwitch port groups are separate, so they don't team at the virtual switch level. Option A is incorrect because teaming at vSwitch is per port group, not across port groups. Option B is incorrect because MAC address changes are not needed. Option D is incorrect because route based on IP hash is for a single port group.

Answer

Enable MAC address changes on both port groups.

Answer

Configure teaming on the standard switch by bridging the two port groups.

Answer

Set load balancing to 'Route based on IP hash' on both port groups.

Question 9

A vSphere administrator notices that after adding a new ESXi host to a vSphere Distributed Switch (vDS), some VMs on existing hosts lose network connectivity intermittently. What is the most likely cause?

Accepted Answer

The vDS MTU setting does not match the physical network MTU.. Option D is correct because if the Maximum Transmission Unit (MTU) is inconsistent across the vDS and physical network, it can cause packet drops and intermittent connectivity. Option A is incorrect because a physical uplink failure affecting all VMs is unlikely to occur only after adding a new host. Option B is incorrect because LACP issues would cause complete failure or reduced throughput, not intermittent connectivity on existing hosts. Option C is incorrect because Network I/O Control is about bandwidth allocation, not connectivity loss.

Answer

The new host's physical uplink is faulty, causing broadcast storms.

Answer

The vDS is configured with LACP, and the new host's links are not properly bundled.

Answer

The vDS Network I/O Control settings are not evenly distributed.

Question 10

Which TWO of the following are valid considerations when configuring a vSphere Distributed Switch with 10G uplinks and planning for a TCP/IP stack for vMotion? (Select exactly two.)

Accepted Answer

Enable vMotion to use a separate TCP/IP stack to avoid competing with management traffic.. Options A and D are correct. A dedicated TCP/IP stack for vMotion isolates vMotion traffic and avoids contention. Using a separate VMkernel interface with a dedicated stack is standard. Option B is incorrect because the storage TCP/IP stack is for NFS/iSCSI, not vMotion. Option C is incorrect because the default TCP/IP stack is a single stack; you need a dedicated stack for isolation. Option E is incorrect because jumbo frames are an MTU setting on the vDS, not a TCP/IP stack component.

Answer

Configure the default TCP/IP stack to handle vMotion traffic with multiple gateways.

Answer

Enable jumbo frames on the vMotion TCP/IP stack to improve performance.

Answer

Use the provisioned TCP/IP stack for vMotion to leverage storage traffic isolation.

Question 11

Which TWO of the following are functions of a vSphere Distributed Switch that are not available in a vSphere Standard Switch? (Select exactly two.)

Accepted Answer

Port mirroring (Distributed Port Mirroring).. Options B and C are correct. Network I/O Control (NIOC) is only available on vDS. Port mirroring (using Distributed Port Mirroring) is a vDS-only feature. Option A is incorrect because VLAN tagging is available on both switch types. Option D is incorrect because NIC teaming is available on standard switches as well. Option E is incorrect because traffic shaping is available on standard switches (per port group).

Answer

NIC teaming with explicit failover order.

Answer

Traffic shaping policies.

Answer

VLAN tagging and trunking.

Question 12

Which THREE of the following are prerequisites for configuring LACP on a vSphere Distributed Switch? (Select exactly three.)

Accepted Answer

The vSphere Distributed Switch must be configured with enhanced LACP support.. Options A, C, and D are correct. LACP requires compatible physical switches, the vDS must be in enhanced LACP mode, and the physical switch ports must be configured as LACP trunks. Option B is incorrect because the uplinks must be connected to the same physical switch to form a LAG; using different switches requires Multi-chassis LACP. Option E is incorrect because LACP does not require separate VLANs; it aggregates links regardless of VLAN config.

Answer

Each uplink must be in a separate VLAN to avoid loops.

Answer

The uplinks must be connected to different physical switches for redundancy.

Question 13

An ESXi host has two VMkernel interfaces as shown in the exhibit. The iSCSI targets are on the same subnet as vmk1 and support jumbo frames. The administrator reports that iSCSI sessions are experiencing high error rates and poor performance. What is most likely the cause?

Accepted Answer

The vDS port group for iSCSI does not have jumbo frames enabled (MTU 9000).. Option C is correct because vmk1 is on a vDS (dvs1) and the exhibit shows MTU 9000, which is appropriate for jumbo frames. However, if the physical network is not configured for jumbo frames or the vDS port group MTU is not set to 9000, fragmentation may occur. The exhibit does not show vDS MTU, but the mismatch is a common cause of errors. Option A is incorrect because management traffic on vmk0 is separate and irrelevant. Option B is incorrect because different subnets are fine. Option D is incorrect because the iSCSI vmkernel port is dedicated.

Answer

The management network (vmk0) is also using the vDS, causing traffic interference.

Answer

The iSCSI VMkernel port should not be bound to a vDS.

Answer

The iSCSI network (vmk1) is on a different subnet than the iSCSI targets.

Question 14

Based on the Healthcheck output for a distributed port (DVS Port 1) on dvs0, what can be concluded?

Accepted Answer

The physical switch is correctly configured for VLAN 100 and MTU 1500 on the uplinks connected to this host.. Option A is correct because the Healthcheck shows VLAN ID 100 and MTU 1500 with 'OK' status, indicating the physical network is properly configured for those values. Option B is incorrect because the Healthcheck does not evaluate speed/duplex. Option C is incorrect because the teaming policy is shown as 'Route based on originating virtual port', which is a valid policy. Option D is incorrect because the Healthcheck does not measure performance; it only checks configuration consistency.

Answer

The uplinks vmnic0 and vmnic1 are operating at 10 Gbps.

Answer

The load balancing policy is set to 'Route based on IP hash'.

Answer

The port is experiencing high packet loss due to misconfiguration.

Question 15

A large financial organization has a vSphere cluster with 10 ESXi hosts (8.x) connected to a pair of Nexus 9000 switches via two 10G LACP link aggregation groups (LAGs) per host. Each host has a vSphere Distributed Switch (vDS 7.0.3) with two LAGs (LAG1: vmnic0, vmnic1; LAG2: vmnic2, vmnic3). The vDS has three port groups: Production (VLAN 100-200), DMZ (VLAN 300), and Storage (VLAN 400). The port groups use LACP with load balancing 'Route based on IP hash'. Recently, the network team changed the physical switch port channels from mode 'active' to 'passive' on the downstream ports connected to host #3, without informing the virtualization team. Within hours, VMs on host #3 experience intermittent connectivity; some can communicate but others cannot, and vMotion between host #3 and other hosts fails with a network unreachable error. iSCSI storage traffic from host #3 is also unstable. The administrator verifies that the vDS LACP configuration on host #3 still expects 'active' mode. Which of the following actions is the most effective to restore full functionality while maintaining LACP?

Accepted Answer

Remove and recreate the LAGs on host #3's vDS after verifying the physical switch's LACP configuration.. Option B is correct because the mismatch in LACP mode (vDS expects active, physical switch is passive) causes LACP to fail or form incorrectly. Changing the vDS LACP mode on host #3 to 'passive' would allow it to negotiate with the physical switch (passive+passive will not form LACP; but if switch is passive, vDS must be active or both active? Actually, LACP requires at least one end active. If switch is passive and vDS is passive, LACP will not establish. The physical switch is now passive, so vDS must be active to initiate negotiation. Wait: The issue is the switch changed to passive. With vDS active, active+passive works. But the stem says 'the vDS LACP configuration on host #3 still expects active mode' – that should work with switch passive? Actually, active+passive does work because active sends frames, passive responds. So why is it failing? Possibly the physical switch changed to passive, but the vDS still has active, but active+passive should work. Let me reconsider: The error might be due to misconfiguration of LAG IDs. The correct action is to re-sync the LAG. Option A (recreate LAG) is drastic. Option C (disable LACP) is not maintaining LACP. Option D (use separate standard switches) is unnecessarily complex. Maybe the best is to update the vDS to match the physical switch's LACP mode? Actually, active+passive works. Perhaps the physical switch change also affected the LAG port-channel configuration. The most direct fix is to ensure both ends are consistent. The vDS expects active, but the switch might have changed to passive and also changed the LAG hash or something. The question wants the most effective action to restore functionality while maintaining LACP. Option B: Reconfigure the vDS LACP on host #3 to match the physical switch's mode (passive). But if both are passive, no LACP. Option A: Recreate the LAGs on the vDS after verifying physical switch configuration. That might be better. Actually, the correct answer is likely A because the issue might be more than just mode mismatch; the LAG IDs might not match. The most reliable step is to recreate the LAGs on the vDS after confirming physical switch config. I'll go with A. However, I need to ensure consistency. Let me think: The vDS LACP modes are active/passive. If the physical switch is now passive, the vDS should be active for LACP to form. But the stem says the vDS expects active, which should work. So why is it failing? Possibly because the physical switch is not sending LACPDUs (passive listens but doesn't initiate). If the vDS is active, it sends LACPDUs, and the passive switch responds. That should work. So maybe the problem is that the physical switch also changed the LAG port-channel ID or the member ports. Therefore, simply changing the vDS mode to passive would cause both ends to be passive, no LACP formation. That would make things worse. So the best action is to verify and reconcile the physical switch configuration (maybe change it back to active) but the admin cannot change physical switch? The question asks what the virtualization admin should do. Option A: Recreate the LAGs after verifying the physical switch configuration. That includes ensuring LACP modes match and IDs match. That is most effective. Option B is incorrect because changing vDS to passive on host #3 could break LACP if switch is also passive. Option C would remove LACP but not maintain it. Option D is a major change. So I'll set A as correct.

Answer

Change the LACP mode on host #3's vDS from 'active' to 'passive' for both LAGs.

Answer

Disable LACP on host #3's vDS and use static EtherChannel instead.

Answer

Replace the vDS with multiple standard switches and use active/standby failover.