Network Level Authentication
Network Level Authentication (NLA) is a feature of Remote Desktop Services (RDP Server) or Remote Desktop Connection (RDP Client) that requires the connecting user to authenticate themselves before a session is established with the server. Originally, if a user opened an RDP (remote desktop) session to a server it would load the login screen from the server for the user. This would use up resources on the server, and was a potential area for denial of service attacks as well as remote code execution attacks (see BlueKeep). Network Level Authentication delegates the user's credentials from the  client through a client-side Security Support Provider and prompts the user to authenticate before establishing a session on the server. Network Level Authentication was introduced in RDP 6.0 and supported initially in Windows Vista. It uses the new Security Support Provider, CredSSP, which is available through SSPI in Windows Vista. With Windows XP Service Pack 3, CredSSP was introduced on that platform and the included RDP 6.1 Client supports NLA; however CredSSP must be enabled in the registry first. Advantages. The advantages of Network Level Authentication are: