Details

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.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

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#’

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_VMW_vSphere_6-5_Y21M10_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system VMware.

References

• 800-53|CM-6b.
• CAT|II
• CCI|CCI-000366
• Rule-ID|SV-216842r612237_rule
• STIG-ID|VCWN-65-000020
• STIG-Legacy|SV-104581
• STIG-Legacy|V-94751
• Vuln-ID|V-216842

Source

• Tenable.com/audits