Frequently asked questions about ServerXMLHTTP (290761)

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1. What is ServerXMLHTTP?
   
   ServerXMLHTTP provides methods and properties for server-safe HTTP access between different Web servers. You can use this object to exchange XML data between different Web servers.
   
   
2. How do you install ServerXMLHTTP?
   
   ServerXMLHTTP is included with the Microsoft XML Parser (MSXML) version 3.0 or later. You can download and install MSXML 3.0 from the following Microsoft Developer Network (MSDN) Web site:

   http://www.microsoft.com/downloads/details.aspx?amp;displaylang=en&familyid=8167837e-0983-4988-99a4-377ef5c0da2e&displaylang=en

3. What are the platform requirements for ServerXMLHTTP?
   
   ServerXMLHTTP support is only available on computers that have Microsoft Windows 2000 installed or on computers that have Microsoft Windows NT 4.0 with Microsoft Internet Explorer 5.01 (or later) installed. It fails on other platforms, such as Microsoft Windows 95 and Microsoft Windows 98.
   
   Using XMLHTTP in server side applications like Active Server Pages (ASP), in components that are hosted in COM+, in components that are used in ASP, or in Windows Services is not supported because XMLHTTP uses WinInet internally. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

   238425 WinInet not supported for use in services

   
   
4. What is the difference between XMLHTTP and ServerXMLHTTP?
   
   XMLHTTP is designed for client applications and relies on URLMon, which is built upon Microsoft Win32 Internet (WinInet). ServerXMLHTTP is designed for server applications and relies on a new HTTP client stack, WinHTTP. ServerXMLHTTP offers reliability and security and is server-safe. For more information, see the MSXML Software Development Kit (SDK) documentation.
   
5. How do you choose between XMLHTTP and ServerXMLHTTP?
   
   As the name suggests, ServerXMLHTTP is recommended for server applications and XMLHTTP is recommended for client applications. XMLHTTP has some advantages such as caching and auto-discovery of proxy settings support. It can be used on Windows 95 and Windows 98 platforms, and it is well-suited for single-user desktop applications.
   
   
6. What is the Proxy Configuration Utility?
   
   The WinHTTP Proxy Configuration Utility, Proxycfg.exe, allows you to configure WinHTTP to access HTTP and HTTPS servers through a proxy server. Because the ServerXMLHTTP component depends on WinHTTP proxy settings, an administrator can use the Proxycfg.exe utility as part of the deployment and installation process of an application that uses WinHTTP. For more information, see the following Microsoft Knowledge Base article:

   289481 You may need to run the Proxycfg tool for ServerXMLHTTP to work

7. Does ServerXMLHTTP support SSL and Digital Certificates?
   
   The ServerXMLHTTP and XMLHTTP components have limited HTTPS support in MSXML3. Specifically, they do not fully support Secure Sockets Layer (SSL) certificates, which are used for authentication. The components do support the HTTPS protocol, but the request fails if the server requires a client certificate.
   
   ServerXMLHTTP includes SSL certificate support in MSXML 3.0 Service Pack 1.
   
   
8. What are the benefits of ServerXMLHTTP?
   • By using ServerXMLHTTP, XML data can be exchanged between local and remote systems as a stream or as XML documents.
   • Because the underlying protocol is HTTP or HTTPS, data can be exchanged between the systems that are behind firewalls.
   • ServerXMLHTTP can be used to send HTTP requests from different environments such as Active Server Pages (ASP), Microsoft Visual Basic, and Microsoft Visual C++.
9. What are the limitations of ServerXMLHTTP?
   
   The number of instances of ServerXMLHTTP that can exist simultaneously within a single process primarily depends upon the amount of memory available for applications on the system. However, other factors, such as CPU processing capacity, or available socket connections can further limit the number of instances that can be active simultaneously.
   
   With MSXML 3.0, the maximum number of instances that can exist simultaneously within a single process is 5,460.
   
   
10. Where can I find more information on ServerXMLHTTP?
    
    Most of the information in this article is gathered from the MSXML SDK, which can be downloaded from the XML section of the following MSDN Web site:

    http://msdn.microsoft.com/xml/default.asp

    This site has the latest information on MSXML technologies.