When using Windows XP SP3 with remote desktop on a Windows Vista or Server 2008 computer that requires NLA or Network Level Authentication you might run into the following error:

"The remote computer requires Network Level Authentication, which your computer does not support. For assistance, contact your system administrator or technical support."

 The problem arises because the Security Provider in Windows XP designed to handle NLA is turned off by default. Don't ask me why. The provider is called "CredSSP" and according to Microsoft here is what it does:

"CredSSP is a new Security Service Provider (SSP) that is available in Windows XP SP3 by using the Security Service Provider Interface (SSPI). CredSSP enables a program to use client-side SSP to delegate user credentials from the client computer to the target server. (The target server is accessed by using server-side SSP). Windows XP SP3 involves only the client-side SSP implementation. The client-side SSP implementation is currently being used by Remote Desktop Protocol (RDP) 6.1 Terminal Services (TS). However, the client-side SSP implementation can be used by any third-party program that is willing to use the client-side SSP to interact with programs that are running server-side SSP implementations in Windows Vista or in Windows Server 2008."

However, the good news is Microsoft also provides a very detailed process on how to turn on CredSSP. I have provided a link to the KB article that describes how to turn on CredSSP. Follow the process under "How to Turn on CredSSP" and the message should be resolved.

http://support.microsoft.com/kb/951608

-Brent

As many people have found out over the past couple of months Microsoft has released the newest version of the Remote Desktop Client. The current version is 6.1. However, as many more of you have found out, the 6.1 client is not supported or released for Windows Server 2003. For many users and admins this is not an issue, but for those of use using Terminal Servers 2008 on a Windows Server 2008 box it raises a few problems. The biggest problem is that the 6.1 client is required to utilize RemoteApps (Similar to Citrix). For common user use this is not a big issue, however for administrative and testing purposes it can be a problem.

The 6.1 RDC is available for the following systems:

1. Windows Server 2008
2. Windows Vista SP1
3. Windows XP SP3

I have been able to find a solution, while not support or sanctioned by Microsoft it seems to do the trick. After users complained (and rightly so) about not being able to get the 6.1 client for Windows XP SP2 Microsoft released a Hotfix to allow those users to install and use it. Personally I recommend upgrading to SP3 as it is pretty solid and stable. I have not had a lot of users experiencing problems with it. So to install the RDC 6.1 for Windows Server 2003 do the following:

1. Visit: http://www.microsoft.com/downloads/details.aspx?FamilyId=6E1EC93D-BDBD-4983-92F7-479E088570AD&displaylang=en
2. Download the XP SP2 Client
3. Once Downloaded the application needs to be run in XP SP2 compatibility mode
   1. Right-Click the installer
   2. Select Properties
   3. Check the "Enable Compatibility box"
   4. Select "Windows XP"
   5. Apply and Close
4. Run the installer – follow the prompts and complete the installation

Ta-da RDC 6.1 for Windows Server 2003