HCX - NSX VDR MAC address change breaks connectivity over extended datapath

Products

• VMware HCX

Issue/Introduction

In an HCX Network Extension scenario where NSX is in use, using a VDR MAC address other then the default value of 02:50:56:56:44:52 results in communication problems between cloud site VMs and the on Prem site resources.

Environment

VMware HCX

VMware NSX

Cause

On the Cloud side, HCX Network Extension (NE-R) appliance configures MAC NAT rule which is programmed with the default VDR MAC address of 02:50:56:56:44:52. As a result, any modification in the VDR MAC address will impact traffic sent from cloud VMs to the on Prem resources over extended data path.

Resolution

Revert the NSX VDR MAC address back to the default value of 02:50:56:56:44:52.

Note: It may incur a momentary downtime while devices re-learn the new MAC address. Please ensure that the implications to NSX regarding the modification of the NSX VDR MAC are understood before making any changes.

Additional Information

From HCX 4.5 Onwards, Network Extension supports for Custom DLR MAC Addresses only where the source VDR MAC has been changed from the default.

IMPORTANT: Currently, there is no support for a non-default VDR MAC at the target site.