MSXML installs and depends upon Microsoft® Windows® HTTP Services (WinHTTP). WinHTTP is a server-side component that provides an updated Hypertext Transfer Protocol (HTTP) stack for developing server-based applications for the Web.

MSXML uses WinHTTP for the ServerXMLHTTP object, a server-side interface for handling HTTP requests. This object differs from the XMLHTTP object, which performs in a similar role as a client-side interface on most computers running Windows. The primary difference between these two interfaces is that XMLHTTP cannot be used in a server environment. This is because it depends upon the WinInet component, which was not designed to provide adequate performance in server-side use.

WinHTTP provides support for the following technologies that you may be using in a Web-based application:

  • Active Server Pages (ASP)

  • Internet Server Application Programming Interface (ISAPI) extensions for Internet Information Services (IIS)

System_CAPS_ICON_note.jpg Note

WinHTTP 5.1 ships with Windows Server 2003. This version of WinHTTP will work side-by-side with earlier versions such as WinHTTP 5.0 that were available in Windows 2000.