RDP from XP to Server 2008 and higher – NLA

Windows XP does support Network Level Authentication (NLA) but it’s not enabled by default. You need Service Pack 3 and version 6.1 of the Remote Desktop Client. Once these are installed make the following two registry changes, then reboot:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
\Lsa\Security Packages
Add tspkg

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
\SecurityProviders\SecurityProviders
Add credssp.dll