title: Which one to consider as machine's fixed and unique MAC id?
body: <p>I need to read a machine's MAC id in C# which stays fixed irrespective of the connection types e.g. connected to Work through network cable, wifi, VPN through Home wifi, through a Dongle or even can be offline.</p>
  <p>So basically it need not necessarily be the MAC id of network interface which is &quot;Up&quot;, i just need the MAC id which is/stays constant.</p>
  <p>With the help of answers in the below link and other suggestions,</p>
  <p><a href="https://stackoverflow.com/questions/850650/reliable-method-to-get-machines-mac-address-in-c-sharp">Reliable method to get machine&#39;s MAC address in C#</a></p>
  <p>I am able to read the MAC ids, but still don't understand which one to consider that will reliably give me the fixed MAC id, which i can use in my application for some sort of verification in that particular system.</p>
  <p>Here are the details of all network interfaces of that system, when the system is connected to &quot;Work&quot; through VPN using Home Wifi and connected to &quot;Work&quot; network directly:</p>
  <p><a href="https://i.stack.imgur.com/5itOW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5itOW.png" alt="Details of all network interfaces of that system" /></a></p>
  <p>Please suggest which one i should consider and what should be the right condition to filter out the interface with fixed MAC id in C#.</p>