Windows Small Business Server (SBS) (formerly Microsoft Small Business Server) is an integrated server suite from Microsoft designed for running network infrastructure (both intranet management and Internet access) of small and medium enterprises having no more than 75 workstations or users. Application server technologies are tightly integrated to enable small businesses with targeted solutions such as the Remote Web Workplace, and offer management benefits such as integrated setup, enhanced monitoring, a unified management console, and remote access.

Windows Small Business Server is technically not an 'edition' of the Windows Server operating system but rather a customized SKU of server technologies targeted especially to small businesses. As such, the application servers are not merely bundled with the OS but are tightly integrated into the operating system. The same service packs as those for Windows Server or other server products cannot simply be used to update the OS.

Editions

Windows Small Business Server is available in Standard and Premium editions. Both editions are based on the Windows Server codebase and include Microsoft Exchange Server mail server, Internet Information Services (IIS) web server, Windows SharePoint Services for collaboration, Microsoft Office Outlook 2003 email client, Routing and Remote Access Service (RRAS), Windows Server Update Services for update management across the network, and a Fax server. Up to SBS 2003, the Premium edition also included Microsoft SQL Server, Microsoft Internet Security and Acceleration Server and Microsoft Office FrontPage 2003. SBS 2008 Premium edition will not include ISA Server but will include a Windows Server 2008 license and SQL Server 2008 for running on a second server. Those upgrading to SBS 2008 Premium edition via Software Assurance will be compensated with a free license for the latest version of ISA Server.

Initially, Small Business Server was marketed as an edition of Microsoft BackOffice Server. When Windows 2000 was released, it was marketed as Microsoft Small Business Server 2000, and finally was rebranded as a member of the Windows Server 2003 family. Microsoft has also introduced a Windows Essential Business Server product aimed at medium-sized businesses, which will now incorporate the next version of ISA Server instead of SBS.

Design and licensing considerations

Windows Small Business Server has its own type of Client Access License (CAL), that is different and costs slightly more than CALs for the usual editions of the Windows Server operating system. However, the SBS CAL encompasses the user CALs for Windows Server, Exchange Server and SQL Server, and hence is less expensive than buying all the other CALs individually.