For the ESXi host all port groups must not be configured to VLAN values reserved by upstream physical switches.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-207664	ESXI-65-000065	SV-207664r388482_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 ESXi Security Technical Implementation Guide	2021-09-22

Details

Check Text ( C-7919r364391_chk )
From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. For each virtual switch, 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 ESXi host run the following command: Get-VirtualPortGroup \| Select Name, VLanId If any port group is configured with a reserved VLAN ID, this is a finding.

Check Text ( C-7919r364391_chk )

From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. For each virtual switch, 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 ESXi host run the following command:

Get-VirtualPortGroup | Select Name, VLanId

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

Fix Text (F-7919r364392_fix)
From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. Highlight a port group (where VLAN ID set to 4095) and click Edit settings (pencil). Change the VLAN ID to not be a reserved VLAN ID and click OK. or From a PowerCLI command prompt while connected to the ESXi host run the following command: Get-VirtualPortGroup -Name "portgroup name" \| Set-VirtualPortGroup -VLanId "New VLAN#"

Fix Text (F-7919r364392_fix)

From the vSphere Web Client select the ESXi Host and go to Configure >> Networking >> Virtual switches. Highlight a port group (where VLAN ID set to 4095) and click Edit settings (pencil). Change the VLAN ID to not be a reserved VLAN ID and click OK.

or

From a PowerCLI command prompt while connected to the ESXi host run the following command:

Get-VirtualPortGroup -Name "portgroup name" | Set-VirtualPortGroup -VLanId "New VLAN#"