There are four editions of Windows Server 2003: Web Edition, Standard Edition, Enterprise Edition, and Datacenter Edition. Web Edition is optimized for hosting websites and has limited features. Standard Edition supports up to two processors and 4GB of RAM and includes features like Active Directory and IIS. Enterprise Edition adds high-level memory management and session management for Terminal Services. It also supports eight-node clustering and booting from SAN. Datacenter Edition supports from 8 to 32 processors and 64GB of RAM and two to eight node clusters, and has the same features as Enterprise Edition except for more extensive firewalling.