Why Are ADFS Binaries Installed on non-R2 Windows Server 2003 computers?

Hi, Warren here. I recently worked on a case where I got to do a bit of sleuthing. I found the results interesting and thought other Windows Server admins might notice the same thing this particular administrator had and wonder why.

My customer has an all Windows 2003 Standard Edition environment. Windows 2003 R2 servers are not deployed. All the servers are built from a carefully managed image. No files are to be allowed on the image if they cannot be accounted for.

This administrator noticed that on all of his servers there is an Active Directory Federated Services (ADFS) directory (%systemdrive%ADFS) complete with the ADFS binaries. He also has noticed that some of the servers have the ADFS binaries installed in the .NET Global Assembly Cache (GAC) while others do not. The GAC is located at %systemroot%assembly.

This is only interesting because ADFS is only available on Windows Server 2003 R2 and Windows 2008. My customer needed to know how and why these ADFS files are installed on his servers and why some of his servers had the ADFS binaries installed in the GAC while others did not.

After researching and testing I was able to determine the root cause of the issue. ADFS binaries will be installed on Windows 2003 Standard Edition when hotfix 920764 or Service Pack 2 is installed (as that hotfix is included in SP2).

Now how do we explain why some of the systems had the ADFS binaries installed in the GAC and others did not?

If .NET 2.0 is installed on a normal (non-R2) 2003 server, and you then apply SP2 you will get the ADFS directory created with the ADFS DLLs in itand the ADFS DLLs installed in the GAC.

If .NET 2.0 is not installed when you apply SP2 you still get the ADFS directory with the ADFS DLLs installed in it, but the ADFS DLLs do not get installed in the GAC.

While this is not earth-shaking news, it may prove helpful to those who need to explain where the ADFS directory and files on their servers came from or it may at a minimum provide an interesting bit of Windows trivia.

If you are interested in learning more about ADFS or the GAC start with these links below:

Global Assembly Cache - https://msdn.microsoft.com/en-us/library/yf1d93sz.aspx

Active Directory Federated Services - https://www.microsoft.com/windowsserver2003/techinfo/overview/adfsoverview.mspx

- Warren Williams