Windows Server 2003 R2 Enterprise Edition includes new features and improvements that render it the most dependable, enterprise-ready server operating system Microsoft has ever created. Key technologies introduced in Windows 2000 Server have been enhanced, including network load balancing, server clusters, and the Active Directory service. Active Directory is now faster and more robust over unreliable wide area network (WAN) connections, thanks to more efficient synchronization and replication as well as credential caching in branch office domain controllers.

In addition, Windows Server 2003 R2 Enterprise Edition introduces new technologies, such as a common language runtime that safeguards networks from malicious or poorly designed code. Moreover, the operating system reflects the Microsoft commitment to trustworthy computing, with leaps forward in security functionality, including improved security for Internet Information Services (IIS), public key infrastructure (PKI), and Kerberos, as well as new support for smart cards and biometrics.