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FIX: The System.Net.HttpWebRequest class may not maintain a persistent connection to a proxy in the .NET Framework 2.0

Article ID: 928563 - View products that this article applies to.

SYMPTOMS

In the Microsoft .NET Framework 2.0, the System.Net.HttpWebRequest class may not maintain a persistent connection to a proxy. Additionally, the client may close the connection if the following conditions are true:

The client tries to access a resource by using a proxy and by using an HTTPS (Secure Sockets Layer) connection.
The client uses the HTTP 1.0 protocol for the connection to the proxy.

Integrated Windows authentication requires a persistent connection. If the proxy requires Integrated Windows authentication, you may receive the following error message:

System.Net.WebException: The remote server returned an error: (407) Proxy Authentication Required.

This problem occurs even if the client sets an appropriate proxy credential.

Note This problem does not occur in the Microsoft .NET Framework 1.1.

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CAUSE

This problem occurs because of one of the following reasons:

The client does not send the "Proxy-Connection: Keep-Alive" header for a CONNECT request.
The client closes the connection to the proxy even if the proxy sends back the "Proxy-Connection: Keep-Alive" header for a CONNECT request.

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RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next .NET Framework 2.0 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

(http://support.microsoft.com/contactus/?ws=support)

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

You must have the .NET Framework 2.0 installed to apply this hotfix.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes that are installed on the computer.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.