ISA Server SP2 Adds Features

Service Pack 2 (SP2) for Internet Security and Acceleration (ISA) Server 2004, Microsoft’s firewall, virtual private networking, and content-caching product, not only rolls up all hotfixes issued since the July 2004 release of the Standard Edition and the Feb. 2005 release of the Enterprise Edition but also contains several improvements to existing features and adds a few new features aimed primarily at customers who use ISA Server 2004 to link branch offices to central corporate networks.

New Features

ISA Server 2004 SP2 adds three new features to both editions and enhances an Enterprise Edition feature, but it doesn’t turn the new features on unless the customer makes configuration changes after installation.

Windows Update caching. ISA Server, in addition to being a security firewall, can also cache Hypertext Transfer Protocol (HTTP) and File Transfer Protocol (FTP) files so that repeat requests can be fulfilled locally out of an ISA Server cache rather than retrieving data from the original source or an upstream cache. This local caching improves browser response time and conserves bandwidth on the customer’s Internet or WAN. However, ISA Server 2004’s caching feature did not work with traffic carried over Microsoft’s Background Intelligent Transfer Services (BITS), an HTTP-based file transfer protocol introduced in 2002 that can move files in the background over slow and unreliable network links. BITS can resume interrupted file transfers where they left off and is used by the Windows Update Agent on Windows 2000 and later operating systems to download patch files from the Microsoft Update or Windows Update Web sites, or alternatively from Windows Server Update Services (WSUS) servers inside the organization’s firewall.