I am working on a project that involves VMware Player. I need to understand if there is a predicatable method Player uses to decide on the MAC
address for the VM?
I created and deleted a VM a few times, and it seems like it keeps choosing the same MAC (I removed the .VMX files from the disk too).
I have looked at the documentation and haven't found anything yet. I am guessing that Player uses the same method as Workstation or Server.
I found this article for ESX, but I need to find out if Player uses the same method:
Each virtual network adapter in a virtual machine gets its own unique MAC address. ESX Server attempts to ensure that the network adapters for each virtual machine that are on the same subnet have unique MAC addresses. The algorithm used by ESX Server puts a limit on how many virtual machines can be running and suspended at once on a given machine. It also does not handle all cases when virtual machines on distinct physical machines share a subnet.
A MAC address is a six-byte number. Each network adapter manufacturer gets a unique three-byte prefix called an OUI - organizationally unique identifier - that it can use to generate unique MAC addresses. VMware has two OUIs - one for automatically generated MAC addresses and one for manually set addresses.
The VMware OUI for automatically generated MAC addresses is 00:05:69. Thus the first three bytes of the MAC address that is automatically generated for each virtual network adapter have this value. ESX Server then uses a MAC address generation algorithm to produce the other three bytes. The algorithm guarantees unique MAC addresses within a machine and attempts to provide unique MAC addresses between ESX Server machines.
The algorithm that ESX Server uses is the following:
When the algorithm generates the last 24 bits of the MAC address, the first 16 bits are set to the same values as the last 16 bits of the console operating system's primary IP address.
The final eight bits of the MAC address are set to a hash value based on the name of the virtual machine's configuration file.
On my Player, I observe the following:
I don't have much information about how UUIDs are generated, but you could have a look at the following thread:
If the generator uses hardware information from the host and complete name of the vmx file of the VM, this could explain why when you recreate your VM on the same machine with same name and stored in the same folder, you obtain the same MAC address. But this doesn't sound dangerous as you can't have two VMs with exactly the same VMX files running on the same hardware.
Do MAC addresses generate the same on other software? I know it is automatically generated, but I am just curious. It might be a sort of combined codes of the software, product, keycodes, etc...