Windows Server 2003 Enterprise 25-Client. Designed for medium to large businesses, Windows Server 2003 Enterprise Edition R2 is the recommended operating system for servers running applications such as networking, messaging, inventory, and customer service systems; databases; and e-commerce Web sites. Windows Server 2003 Enterprise Edition R2, delivers high reliability, performance, and superior business value and is available in both 32-bit and 64-bit versions. Windows Server 2003, Enterprise Edition, differs from Windows Server 2003, Standard Edition, primarily in its support for high-performance servers and its ability to cluster servers for greater load handling. These capabilities provide reliability that helps ensure systems remain available even if problems arise. Windows Server 2003 R2 is an update release of the award-winning Windows Server 2003 operating system. Built on Windows Server 2003 with Service Pack 1 (SP1), Windows Server 2003 R2 takes advantage of the stability and security of a proven code base while extending connectivity and control into new areas. Windows Server 2003 R2 offers all the benefits of Windows Server 2003 SP1 while greatly improving branch office server solutions, identity and access management, storage setup and management, and application development inside and outside your organization's traditional boundaries. Windows Server 2003 R2 is easy to integrate into an existing Windows Server 2003 environment as it has the same application compatibility, manageability, and serviceability as the existing servers with SP1.