Connections that use HTTP were introduced with Analysis Services. This connection method allows the PivotTable® Service to tunnel through firewalls or proxy servers to the Analysis Services server. When connecting to Analysis Services by using HTTP, the connection occurs through Microsoft Internet Information Services (IIS). The port used during connection is defined by the default port of the Web site. In most cases, the default port of the Web site is set to 80 (or 443 if Secure Sockets Layer [SSL] is used).
For additional information about connecting to Analysis Services 8.0 by using an HTTP connection, refer to the "Connecting Using HTTP" topic in SQL Server Books Online.