Internal Proxy Clients Receive the IIS Default Web Site When Browsing to a Site on the Proxy Server (243248)

SYMPTOMS

When an internal Web Proxy client attempts to access a Microsoft Internet Information Server (IIS) 4.0 Web site that is hosted on the Proxy server, the Proxy server's default Web site home page is returned to the browser.

This problem occurs only when the client attempts to gain access to a site by using a fully qualified Web address (also known as an FQDN or IP address).

CAUSE

When a Web browser is configured to use a Hypertext Transfer Protocol (HTTP) Proxy server, the browser parses the Web address for periods (or dots) to determine if the destination site is local or remote. All fully qualified domain names are considered remote and are sent to the Proxy server for handling. All Web addresses that contain non-qualified names (for example, http://servername) are considered to be local; the browser makes the request to the site directly.

A Proxy server should not handle a Proxy request for a site located on the Proxy server itself. Proxy Server 2.0 does not hand the request off to the correct local site and returns the default Web site home page.

RESOLUTION

Clients that are accessing intranet Web sites on the local network should send the request directly to the publishing server, not to the Proxy server. There are four independent ways to make sure that the request is sent to the publishing server directly:

Add an entry to the HOSTS file on the Proxy server. The IP address associated with the FQDN must be the internal IP address of the webserver. The HOSTS file is located in %SystemRoot%\system32\drivers\etc. Please see Q105997 Differences Between the HOSTS and LMHOSTS Files in Windows NT for assistance in adding entries to the HOSTS file.
Have the user type the Web address as a non-qualified name (without periods), such as http://servername.
If the Web browser (such as Microsoft Internet Explorer) supports proxy domain exclusions in the HTTP Proxy configuration, configure a domain exclusion for the local domain name. For example, if the intranet Web server has an address of http://www.servername.com, specify a proxy domain for "*.servername.com" (without the quotation marks). The browser then sends a Web request to all addresses ending in "servername.com" directly to the Web server and not to the HTTP Proxy.
Configure the Web browser to use the Proxy http://proxyserver:80?Get.Routing.Script automatic configuration script. Configure the Proxy server for the domain exclusion "servername.com" (without the "*." or quotation marks) in the server's Web Proxy Client Configuration properties. The browser requests the automatic configuration file when the browser starts and downloads the domain exclusions from the server. The browser then sends a Web request to all addresses ending in "servername.com" directly to the Web server and not to the HTTP Proxy.

MORE INFORMATION

This behavior occurs only for internal Proxy clients. External requests from clients on the Internet are handled by the Proxy server's Web Publishing feature and are directed to the correct site based on the Web address. Web Publishing allows an administrator to configure mappings so that requests for certain Web addresses from Internet clients are forwarded to the local Web server or to any number of internal Web servers.

For additional information about Web Publishing, see the Proxy Server 2.0 online documentation and the following article in the Microsoft Knowledge Base:

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