The vCenter Server for Windows must not configure all port groups to VLAN values reserved by upstream physical switches.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-94751	VCWN-65-000020	SV-104581r1_rule		Medium

Description
Certain physical switches reserve certain VLAN IDs for internal purposes and often disallow traffic configured to these values. For example, Cisco Catalyst switches typically reserve VLANs 1001–1024 and 4094, while Nexus switches typically reserve 3968–4047 and 4094. Check with the documentation for your specific switch. Using a reserved VLAN might result in a denial of service on the network.

Description

Certain physical switches reserve certain VLAN IDs for internal purposes and often disallow traffic configured to these values. For example, Cisco Catalyst switches typically reserve VLANs 1001–1024 and 4094, while Nexus switches typically reserve 3968–4047 and 4094. Check with the documentation for your specific switch. Using a reserved VLAN might result in a denial of service on the network.

STIG	Date
VMware vSphere 6.5 vCenter Server for Windows Security Technical Implementation Guide	2020-03-27

Details

Check Text ( C-93941r1_chk )
From the vSphere Web Client go to Networking >> Select a distributed switch >> Select a distributed port group >> Configure >> Settings >> Policies. Review the port group VLAN tags and verify they are not set to a reserved VLAN ID. or From a PowerCLI command prompt while connected to the vCenter server run the following command: Get-VDPortgroup \| select Name, VlanConfiguration If any port group is configured with a reserved VLAN ID, this is a finding.

Check Text ( C-93941r1_chk )

From the vSphere Web Client go to Networking >> Select a distributed switch >> Select a distributed port group >> Configure >> Settings >> Policies.

Review the port group VLAN tags and verify they are not set to a reserved VLAN ID.

or

From a PowerCLI command prompt while connected to the vCenter server run the following command:
Get-VDPortgroup | select Name, VlanConfiguration

If any port group is configured with a reserved VLAN ID, this is a finding.

Fix Text (F-100869r1_fix)
From the vSphere Web Client go to Networking >> Select a distributed switch >> Select a distributed port group >> Configure >> Settings >> Policies. Click "Edit" and under the VLAN section and change the VLAN ID to an unreserved VLAN ID and click "OK". or From a PowerCLI command prompt while connected to the vCenter server run the following command: Get-VDPortgroup "portgroup name" \| Set-VDVlanConfiguration -VlanId "New VLAN#"

Fix Text (F-100869r1_fix)

From the vSphere Web Client go to Networking >> Select a distributed switch >> Select a distributed port group >> Configure >> Settings >> Policies. Click "Edit" and under the VLAN section and change the VLAN ID to an unreserved VLAN ID and click "OK".

or

From a PowerCLI command prompt while connected to the vCenter server run the following command:
Get-VDPortgroup "portgroup name" | Set-VDVlanConfiguration -VlanId "New VLAN#"