2003 R2 Here

R2 introduced ADFS , a web-based single sign-on (SSO) solution. This allowed organizations to share identity information across different security boundaries, enabling users to access applications in partner organizations using their own corporate credentials.

Even years after its end-of-life, Windows Server 2003 R2 remains a notable milestone in IT history for its introduction of several core technologies still used in modern server environments today. Core Features and Improvements 2003 r2