Heh - "impossible" you say?? We're good here..

It is definitely possible to change the PHYSICAL MAC of a NIC as well..as long as the NIC supports it. (mine does..it's an Intel(R) PRO/100+ Management Adapter) By the way - the loopback does not have a MAC assigned..MAC addresses are only hardware-assigned addresses. But - maybe this might help you.
Here's how:
Some NICs have the ability to change the MAC (Media Access Control) address through software. If you NIC and driver support this, Windows 2000 can change it:
1. Use Control Panel and double-click Network and Dial-up Connections or
Start / Settings / Network and Dial-up Connections.
2. Right-click the the connection (that uses the NIC) and press Properties.
3. Press the Configure button.
4. Select the Advanced tab.
5. Select Locally Administered Address.
6. Enter the new MAC address value.
You can also use the registry to make this change. Use Regedt32 to navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<Your NIC>
On the Edit menu, Add Value name <Old MAC Address>, as a REG_SZ data type. Enter the new MAC address into the String Editor.
You must restart your computer for the change to take effect.
After the restart, open a CMD prompt and type:
net config rdr
Verify the new MAC address.
Windows 2000 is more powerful than most people realize - the features are well hidden to keep regular users away from things such as this. It's a risky move for an uninformed regular user. Im surprised myself that this isn't restricted to registry-editing only. But - thats how you do it.
*Note.. If using DHCP or reservations, this will have to be changed in DHCP. Also note that there is often a period of sometimes 10 minutes where your PC will not seem to communicate with anything. This is normal..the ARPcache needs to be refreshed so to say..after changing the address, be patient. Often you will not be able to login for a little while.
Happy hacking

pbxman
Systems Administrator
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