Using the XMLHTTP object on the server side is not recommended because the XMLHttpRequest support in MSXML sends HTTP requests using the Internet Explorer URLMON and WININET components. These components were designed and tested only to be used from a client machine in a regular user process. The Microsoft® Internet Information Server (IIS) and ASP system runs in a protected server service that imposes performance and security constraints on server applications that breaks some of the functionality of URLMON and WININET. Microsoft recommends using either the ServerXMLHttp or, better yet, the new System.Net.WebRequest that is part of the .NET Framework for XML requests on the server.