Mac Address For Vm

Summary

#Range or PrefixVendorVirtual Machine
100:50:56VMWareVMware vSphere, VMware Workstation, VMware ESX Server
200:50:56:80:00:00 → 00:50:56:BF:FF:FFVMWareVMware vSphere managed by vCenter Server
300:0C:29VMWareStandalone VMware vSphere, VMware Workstation, VMware Horizon
400:05:69VMWareVMware ESX, VMware GSX Server
500:1C:14VMWareVMWare

Yes, the MAC address ranges that are used by virtual machines all over the world are reused. However, MAC addresses only need to be unique on the local layer 2 network. Anything on the other side of a router doesn't know or care what your local MAC addresses are. Powershell to get all MAC addresses of each virtual machine on a host and export to tab delimited file By mindaugas May 21, 2015 Tech, Uncategorized Leave a comment This will spit out the MAC address and name of each virtual machine on a host to a text file. VMware OUI in Static MAC Addresses By default, static MAC addresses have the VMware Organizationally Unique Identifier (OUI) as the prefix. However, the range of free address provided by the VMware OUI is restricted. Assign a Static MAC Address You can assign static MAC addresses to the virtual NIC of a powered off virtual machine by using the vSphere Client.

OUIs registered by VMWare, Inc

There are 4 OUIs registered by VMware, Inc:

OUI Assignment Type
00:50:56MA-L
00:1C:14MA-L
00:0C:29MA-L
00:05:69MA-L

Detection Rule 1

Affects products: VMware vSphere, VMware Workstation, VMware ESX Server

Signature: OUI is 00:50:56

Conditions

When the administrator assigns the MAC address manually to a virtual machine, this OUI prefix is set automatically. The last 3 octets should be set manually.

However, administrators can set any MAC address to their virtual machines.

References

Example MACs generated

  • 00:50:56:11:22:33
  • 00:50:56:12:23:34
  • 00:50:56:33:A1:BB

Tested on

  • VMware vSphere 5.5, standalone
  • VMware VMware Workstation 15

Detection Rule 2

Affects products: VMware vSphere managed by vCenter Server

Signature: MAC address belongs to the range [00:50:56:80:00:00; 00:50:56:BF:FF:FF]

Conditions

According to the VMware OUI allocation scheme, a MAC address has the format of 00:50:56:XX:YY:ZZ, where 00:50:56 represents the VMware OUI, XX is calculated as (80 + vCenter Server ID), and YY and ZZ are random two-digit hexadecimal numbers.

Based on this scheme, we can determine the vCenter Server Unique ID, from the servers' MAC address:

  • Take the 4th octet: for 00:50:56:97:12:34, it would be 97
  • Subtract 0x80: 0x97 - 0x80 = 0x17
  • Rebase it from Base-16 to to Base-10. In our example, it would be 0x17 → 23
  • vCenter Server Unique ID = 23

References

Example MACs generated

  • 00:50:56:A5:12:34
  • 00:50:56:A5:A0:12
  • 00:50:56:90:A4:BA

Tested on

  • vCenter Server 5.5, 6.5

Detection Rule 3

Affects products: Standalone VMware vSphere, VMware Workstation, VMware Horizon

Signature: OUI is 00:0C:29

Conditions

According to the VMware OUI allocation scheme, the hypervisor generates MAC addresses that consists of the VMware OUI 00:0C:29 and the last three octets of the virtual machine UUID in hexadecimal format. The virtual machine UUID is based on a hash calculated by using the UUID of the ESXi physical machine and the path to the configuration file (.vmx) of the virtual machine.

References

Example MACs generated

  • 00:0C:29:4E:C6:49
  • 00:0C:29:49:92:99
  • 00:0C:29:5C:F3:BA

Tested on

  • vSphere 5.5, 6.5, VMware Workstation 15

Detection Rule 4

Affects products: Outdated VMWare solutions: VMware ESX, VMware GSX Server

Signature: OUI is 00:05:69

Conditions

Mac Address For Vm

According to the VMware OUI allocation scheme, the hypervisor generates MAC addresses that consists of the VMware OUI 00:05:69 and the last three octets generated by the following algorithm:

  • 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.

For example, if a machine's IP address was 192.34.14.81 (or in hex, 0xc0220e51) and the configuration file was hashed to the value of 95, the MAC address would have the following value: 00:05:69:0e:51:95

References:

Example MACs generated

  • 00:05:69:0e:51:95

Detection Rule 5

Affects products: VMware products

Mac Address For Vm

Signature: OUI is 00:1C:14

References:

Mac Address For Vm Configuration

Example MACs generated

  • 00:1C:14:00:11:22

Virtual Machine’s MAC ranges

More questions

I have been asked by many VMware Administrators about how MAC addresses are assigned to Virtual Machine?. We all aware that first 3 octets will be 00:50:56. The first three parts never change. This is the VMware Organizational Unique Identifier (OUI). How do other 3 octets are generated?. This may be the biggest question in our mind? Let’s discuss How MAC addresses are assigned to VMware Virtual Machines by the vCenter server. This post only applies to the VM MAC generation, in which ESXi host is managed by vCenter Server. ESXi host which is not managed by the vCenter server will have the different mechanism to generate the MAC address for Virtual Machine.

How vCenter Assigns Virtual MAC Address to VMware Virtual Machine?

As we aware that, First 3 Octects will be 00:50:56. This is the VMware Organizational Unique Identifier (OUI). How does 4th octet of VM MAC address are calculated? Let’s begin the Calculation.

4th Octet of MAC = (128+ vCenter Instance ID) Convert it to Hexadecimal

To get the vCenter Server Instance ID -> Login to vSphere Client ->Administration -> vCenter Server Settings -> Runtime Settings. Note down the vCenter Server Unique ID. My vCenter Server Unique ID is 24.

How to Calculate 4th Octet of the VM MAC Address?

The automatically generated MAC address has the fourth octet is equal to 128 + the vCenter instance ID converted to hexadecimal.

4th Octet of MAC = (128+ vCenter Instance ID) Convert it to Hexadecimal

= 128+24 = 152

4th Octet of VM MAC = 98 (Conversion of 152 to Hexadecimal)

I have confirmed the Same from the few of Virtual Machine MAC Address. 4 octet is assigned as “98”.

The last two bytes are assigned in the mechanism so that each MAC address is assigned would be unique. I hope this is informative for you. Thanks for Reading!!!. Be Social and share it on social media, if you feel worth sharing it.

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