Windows XP RDP Client network level security

Check for update compliance

For Windows XP to be able to use NLA, it must first be updated to SP3. Additionally, I would suggest installing the RDP v.7 update as well since it brings the full functionality of NLA into play.

http://www.microsoft.com/pl-pl/download/details.aspx?id=20609

Navigate to and modify the registry keys

There are two keys to change. The first is located at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa

You are going to modify the key named 'Security Packages'
Add 'tspkg' to the listing of security packages. Do not remove any packages.

The second key is located at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders

You are going to modify the key named 'SecurityProviders'
Add 'credssp.dll' to the listing of Security Providers.

Close the registry editor.

Restart the computer.

After the restart is complete. Test the NLA functionality by attempting to RDP to a server that only accepts RDP connections from machines that use NLA.

If it works, you have succeeded. If it does not work, then you should check to ensure that the above defined changes have been made correctly.