When changing the MAC address of a virtual machine from Manual to Automatic, 00:0C:29x:x: is set instead of 00:50:56x:x:

Products

• VMware vCenter Server

Issue/Introduction

When changing the MAC address of a virtual machine from Manual to Automatic, 00:0C:29x:x: is set instead of 00:50:56x:x:

 

Environment

VMware vCenter Server 8.0.x
VMware vCenter Server 7.0.3

Cause

• The 00:0c:29:xx:xx:xx MAC address is generated by the host, not by the vCenter.
• When the user change the MAC address from static to automatic , vCenter doesn't capture that configuration change thus it doesn't generate the MAC address for it.
• When the VM gets powered on, host checks if a MAC has been generated in the case the MAC address is set to automatic. In this case, it doesn't find a generated MAC address, thus it generates 00:0c:29 MAC address.

Resolution

Issue is fixed in vCenter 7.0.3 P06 and vCenter 8.0.0.1 P1

Workaround:

 Remove and re-add the vNIC of the impacted VM.

 

Additional Information

Changing MAC type from manual to automatic through vCenter set an unexpected MAC address range of 00:0C:29 instead of 00:50:56