The Advisers Group

Microsoft Windows Server 2003 was released on April 24, 2003. It is the successor to Windows 2000 Server, An updated version, Windows Server 2003 R2 was released on December 6, 2005.

Small Business Server 2003 (SBS 2003) is a specialized version of Windows Server 2003 that contains Windows SharePoint Services for collaboration, Microsoft Exchange server for e-mail, an integrated Fax Server, and the Active Directory for user management.
SBS 2003 also provides a basic firewall, DHCP server and NAT router using either two network cards or one network card in addition to a hardware router.
For business requiring better database and firewall support SBS 2003 Premium Edition  includes the above plus Microsoft SQL Server 2000 and Microsoft Internet Security and Acceleration Server 2004.

Windows Server 2003 and SBS2003 have been succeeded by Windows Server 2008 and SBS2008.