Microsoft Internet Security and Acceleration (ISA) Server 2004 is the advanced stateful packet and application-layer inspection firewall, virtual private network (VPN), and Web cache solution that enables enterprise customers to easily maximize existing information technology (IT) investments by improving network security and performance. ISA Server 2004 is available in two versions: standard edition and enterprise edition. Information included in this product overview includes features and capabilities in both versions, unless otherwise specified.

ISA Server 2004 provides advanced protection, ease of use, and fast, secure access for all types of networks. ISA Server is particularly well suited for protecting large enterprise network configurations requiring multiple firewall arrays in disparate locations that are running Microsoft client and server applications, such as Microsoft Office, Office Outlook Web Access 2003, Office SharePoint Portal Server 2003, Internet Information Services (IIS), Routing and Remote Access, Active Directory directory service, and many other Microsoft applications, servers, and services.

ISA Server contains a full featured, application-layer aware firewall that helps protect organizations of all sizes from attack by both external and internal threats. ISA Server performs deep inspection of Internet protocols such as Hypertext Transfer Protocol (HTTP), which enables it to detect many threats that traditional firewalls cannot detect. The integrated firewall and VPN architecture of ISA Server support stateful filtering and inspection of all VPN traffic. The firewall also provides VPN client inspection for Microsoft Windows Server 2003-based quarantine solutions, helping to protect networks from attacks that enter through a VPN connection. In addition, a completely new user interface, wizards, templates, and a host of management tools help administrators avoid common security configuration errors.