Question : Is there a way to programmatically discover the MAC address of the PHYSICAL NIC used by VPN connections or other virtual interfaces?

Let's say you have the following situation:

PC ---> VPN virtual connection ---> NIC ---> ( Internet cloud ) ---> VPN server ---> Private LAN
                 Private IP                  Public IP

Is there a way to programmatically get the MAC address (using Windows APIs) of the NIC that is used by the VPN connection as the transport medium.

Answer : Is there a way to programmatically discover the MAC address of the PHYSICAL NIC used by VPN connections or other virtual interfaces?

It'll spit out quite a lot of things. Eg. from my PC:

-------------------------------------------------
Description: Intel(R) PRO/100 VE Network Connection
Name: Intel(R) PRO/100 VE Network Connection
Manufacturer:
MAC Address:

Description: RAS Async Adapter
Name: RAS Async Adapter
Manufacturer:
MAC Address:

Description: Packet Scheduler Miniport
Name: Packet Scheduler Miniport
Manufacturer: Microsoft
MAC Address:

Description: WAN Miniport (L2TP)
Name: WAN Miniport (L2TP)
Manufacturer: Microsoft
MAC Address:

Description: WAN Miniport (PPTP)
Name: WAN Miniport (PPTP)
Manufacturer: Microsoft
MAC Address: 50:50:54:50:30:30

Description: WAN Miniport (PPPOE)
Name: WAN Miniport (PPPOE)
Manufacturer: Microsoft
MAC Address: 33:50:6F:45:30:30

Description: Direct Parallel
Name: Direct Parallel
Manufacturer: Microsoft
MAC Address:

Description: WAN Miniport (IP)
Name: WAN Miniport (IP)
Manufacturer: Microsoft
MAC Address:

Description: Packet Scheduler Miniport
Name: Packet Scheduler Miniport
Manufacturer: Microsoft
MAC Address: CC:F6:20:52:41:53

Description: Intel(R) PRO/100 VE Network Connection
Name: Intel(R) PRO/100 VE Network Connection
Manufacturer: Intel
MAC Address: 00:E0:18:4F:E3:E0

Description: Packet Scheduler Miniport
Name: Packet Scheduler Miniport
Manufacturer: Microsoft
MAC Address: 00:E0:18:4F:E3:E0

Description: 1394 Net Adapter
Name: 1394 Net Adapter
Manufacturer: Microsoft
MAC Address: 32:9F:90:F8:37:79

I also noticed that a number of items were returned twice, but only once with a MAC address. The first item returned was the actual ethernet card, but its MAC address was only included with the second instance. MAC Address: 00:E0:18:4F:E3:E0.  I have no idea of what the explanation is for that. :)