How to determine MAC Address of the actual physical network card — not virtual network interfaces created by VPN's (.NET C#)

Question

Background

I\'m trying to get obtain a unique identifier out of a computer and want to be able to reliably return the same MAC address each time. Trust me I have

Answer 1

The first three bytes of the MAC address are a manufacturer ID. You could blacklist certain manufacturer IDs known to be unsuitable for your purposes, and ignore those interfaces.

Relying on the speed is not likely to be a good idea, because there's no reason why a VPN interface couldn't report itself as having gigabit speed.