Use the vSphere Client to enable prefix-based or range-based MAC address allocation and to adjust the allocation parameters.

If you are changing from one type of allocation to another, for example changing from the VMware OUI allocation to a range-based allocation, use the vSphere Client. However, when a schema is prefix-based or range-based and you want to change to a different allocation schema, you must edit the vpxd.cfg file manually and restart vCenter Server.