The non-negotiate option must be configured for trunk links between external physical switches and virtual switches in VST mode.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-63301	ESXI-06-000066	SV-77791r1_rule		Medium

Description
In order to communicate with virtual switches in VST mode, external switch ports must be configured as trunk ports. VST mode does not support Dynamic Trunking Protocol (DTP), so the trunk must be static and unconditional. The auto or desirable physical switch settings do not work with the ESXi Server because the physical switch communicates with the ESXi Server using DTP. The non-negotiate and on options unconditionally enable VLAN trunking on the physical switch and create a VLAN trunk link between the ESXi Server and the physical switch. The difference between non-negotiate and on options is that on mode still sends out DTP frames, whereas the non-negotiate option does not. The non-negotiate option should be used for all VLAN trunks, to minimize unnecessary network traffic for virtual switches in VST mode.

Description

In order to communicate with virtual switches in VST mode, external switch ports must be configured as trunk ports. VST mode does not support Dynamic Trunking Protocol (DTP), so the trunk must be static and unconditional. The auto or desirable physical switch settings do not work with the ESXi Server because the physical switch communicates with the ESXi Server using DTP. The non-negotiate and on options unconditionally enable VLAN trunking on the physical switch and create a VLAN trunk link between the ESXi Server and the physical switch. The difference between non-negotiate and on options is that on mode still sends out DTP frames, whereas the non-negotiate option does not. The non-negotiate option should be used for all VLAN trunks, to minimize unnecessary network traffic for virtual switches in VST mode.

STIG	Date
VMware vSphere ESXi 6.0 Security Technical Implementation Guide	2017-07-11

Details

Check Text ( C-64035r1_chk )
Note: This check refers to an entity outside the physical scope of the ESXi server system. The configuration of external switch ports as trunk ports must be documented. Virtual Switch Tagging (VST) mode does not support Dynamic Trunking Protocol (DTP), so the trunk must be static and unconditional. Inspect the documentation and verify that the documentation is correct and updated on a regular basis and/or whenever modifications are made to either ESXi hosts or the upstream external switch ports. If DTP is enabled on the physical switch ports connected to the ESXi Host, this is a finding.

Check Text ( C-64035r1_chk )

Note: This check refers to an entity outside the physical scope of the ESXi server system. The configuration of external switch ports as trunk ports must be documented. Virtual Switch Tagging (VST) mode does not support Dynamic Trunking Protocol (DTP), so the trunk must be static and unconditional. Inspect the documentation and verify that the documentation is correct and updated on a regular basis and/or whenever modifications are made to either ESXi hosts or the upstream external switch ports.

If DTP is enabled on the physical switch ports connected to the ESXi Host, this is a finding.

Fix Text (F-69219r1_fix)
Note: This check refers to an entity outside the physical scope of the ESXi server system. Document the configuration of external switch ports as trunk ports. Log in to the vendor-specific physical switch and disable DTP on the physical switch ports connected to the ESXi Host. Update the documentation on a regular basis or whenever modifications are made to either ESXi hosts or the upstream external switch ports.

Fix Text (F-69219r1_fix)

Note: This check refers to an entity outside the physical scope of the ESXi server system. Document the configuration of external switch ports as trunk ports. Log in to the vendor-specific physical switch and disable DTP on the physical switch ports connected to the ESXi Host. Update the documentation on a regular basis or whenever modifications are made to either ESXi hosts or the upstream external switch ports.