0

I need to have all the macaddress same for all the VMs that come up in a VMSS. They can be either just changing the registry entry when the VMs come up. Can someone help me with that? Also would that change have any impact in terms of network/security of VMs in VNET even if they are behind load balancer?

Aayam Singh
  • 1
  • 2

2 Answers2

0

MAC Addresses are designed to uniquely identify a network interface in a computer Network.

Having duplicate MAC Addresses in a computer network would cause the network to malfunction (or at least one of the network interfaces will be kicked out and not able to communicate with the network).

The requirement to have same MAC Addresses is fundamentally wrong and shows intent to abuse either software licences that are bound to MAC Address, or some malicious network activity.

If you state your question more detailed (why the requirement for same MAC Addresses, what is the base architecture of the solution) maybe we will be able to help you.

astaykov
  • 30,768
  • 3
  • 70
  • 86
  • We had product that generates license file with unique code using Mac address during manual installation. Now we are trying to move that product to Azure and leverage scale sets for auto scaling. To have that product installed on every new VM that comes up in scale set during load, it needs to have that license file generated to work properly for each VM automatically. Now the problem is I cannot generate the license key on fly everytime with every VM that comes up. Hence will create a license file within custom image and update each VM with relevant mac address. – Aayam Singh Sep 13 '16 at 20:28
  • You cannot update MAC Address of a running Azure VM. Well, technically you can, but the result will be total malfunction of the VM. You have to work out with the software distributor to switch the licensing mode from MAC to IP Address or be more flexible for the licensing. The Virtual machines will retain their MAC Address during Start-stop-deallocate-restart lifecycle. But in a VMSS you basically get new VMs provisioned, so this does not help you. So at the end VMSS is probably not the best suitable solution for your scenario. – astaykov Sep 13 '16 at 21:14
0

What you can do to implement this approach is create a separate subnet within you Azure VNet for Licensing and then add a second NIC that is bound to that Subnet, then set the MAC addresses as you see fit there. This allows you to have normal network connectivity on your primary NIC and the Licenses can be on the MACs associated on the secondary NIC. This approach is laid out in this blog post by Francois DelPort: https://www.francoisdelport.com/2015/10/change-the-mac-address-on-your-azure-vm/

Patrick Simpson
  • 11
  • 3