Proxy Server Always Forwards Requests When Part of a Web Proxy Chain

ID: Q228721

The information in this article applies to:

SYMPTOMS

When Proxy Server is part of a Web Proxy chain, it automatically forwards all requests to the upstream server without recourse to the local LAT table.


CAUSE

This is a design limitation of Proxy Server version 2.0.


RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp
The English version of this fix should have the following file attributes or later:

   Date      Time                 Size    File name     Platform
   -------------------------------------------------------------
   03/23/99  20:22:54          189,200    W3proxy.dll   (x86)
   03/23/99  20:21:11          305,424    W3proxy.dll   (Alpha)
NOTE: This fix is only applicable to Proxy Server 2.0 running on IIS 4.0 with Windows NT Service Pack 4 applied. This fix requires the Proxy Server 2.0 Combined Hotfix to be installed prior to the application of this fix. For additional information about the Proxy Server 2.0 Combined Hotfix, please see the following article in the Microsoft Knowledge Base:
Q190997 Proxy Server 2.0 Combined Hotfix Information and List of Fixes

NOTE: If this product was already installed on your computer when you purchased it from the Original Equipment Manufacturer (OEM) and you need this fix, please call the Pay Per Incident number listed on the above Web site. If you contact Microsoft to obtain this fix, and if it is determined that you only require the fix you requested, no fee will be charged. However, if you request additional technical support, and if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support, you may be charged a non-refundable fee.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:
Q154871 Determining If You Are Eligible for No-Charge Technical Support


STATUS

Microsoft has confirmed this to be a problem in Proxy Server version 2.0.


MORE INFORMATION

With this fix applied, Proxy Server uses an additional registry string in HKLM\SYSTEM\ControlSet\serveices\w3proxy\parameters named "RoutingExceptions." It is a semicolon-separated list of routing "exceptions." Each exception is made up of four space separated components, the first three of which describe the requests that match this exception and cause it to trigger. The format of the exception string is as follows:

<protocol> <domain> <port> <proxy>
where:

<protocol> is the protocol of the request or "*" to match all protocols
<domain> is the destination domain name of the request or "*" to match all domains or "*string" to match domains ending in the given string or the special "NODOTS" value, which matches any domain name that does not include a "." character
<port> is the decimal port number of the request or "*" to match all ports
<proxy> is the name and port number of the proxy server that this request will be routed to or the special "DIRECT" value if the matching URL should be fetched directly without chaining to another proxy.

Except for the special "DIRECT" and "NODOTS" values, strings are case insensitive.

If more than one exception matches a given request, then the first exception listed will be used.

Additional query words: routing 


Keywords          : 
Version           : winnt:2.0
Platform          : winnt 
Issue type        : kbbug

Last Reviewed: July 2, 1999