It’s not widely known that with XP SP3 you are now able to RDP using NLA and is fully supported by Microsoft.
To enable this, all you need to do is ensure that you have SP3 installed on your XP computer and modify two registry entries.
Here’s how: (Note: perform all of the following steps on the XP SP3 computer)
1. In regedit, navigate to the following subkey:
2. In the details pane, right-click Security Packages, and then click Modify. In the Value data box, type tspkg. Leave the other data intact and then click OK.
3. In the navigation pane, locate and then click the following registry subkey:
4. In the details pane, right-click SecurityProviders, and then click Modify. In the Value data box, type credssp.dll. (Ensure you type a comma followed by a space first – see screenshot below) Leave all the other entries intact and then click OK.
5. Exit the registry editor and reboot the computer.
You are now able to RDP from an XP computer using NLA!