How to get MAC w/o network conection

[Pazan]

I have some trouble:

lan = System.GetLANInfo(); 
Paragraph.SetText("IP Address: "..lan.IP.."\nMAC: "..lan.NIC);

When PC is not conected to switch/hub I get result like that:

IP Address: 127.0.0.1
MAC: None

How to get real data not localhost in this case?

[longedge]

If your computer is not connected to a network, you can't get the network address - none exists.

The loopback address is the only one available. Type "ipconfig /all" in a command prompt to show all the information about your IP and network adapter/s.

[Pazan]

So, this not exactly I want. I know about Loopback device and ipconfig command, but I would to get some information about customers PCs.
I need these 2 parameters (IP/MAC) for run projects.
If MAC is in blacklist, project not run on this machine.
Maybe anyone can show other ways to resolve this?