Microsoft KB Archive/222561

= FTP produces "407 Proxy Authentication Required" =

Article ID: 222561

Article Last Modified on 10/19/2005

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APPLIES TO


 * Microsoft Internet Explorer 4.01 Service Pack 1
 * Microsoft Internet Explorer 4.0 128-Bit Edition
 * Microsoft Internet Explorer 3.02
 * Microsoft Proxy Server 2.0 Standard Edition

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This article was previously published under Q222561



SYMPTOMS
When you attempt to use the following syntax to pass FTP logon information from Internet Explorer 4.x through Microsoft Proxy Server 2.0, you are prompted for domain credentials three times.

ftp://username:password@ftp.site.com

The operation fails after the third prompt for domain credentials, and the following error message occurs:

HTTP/1.1

407 Proxy Authentication Required

You must authenticate with a proxy server before this request can be serviced.

Please logon to your proxy server and then try again.



CAUSE
Internet Explorer passes the username and password from the URL as the proxy authentication credentials.



RESOLUTION
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

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

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.

The English version of this fix should have the following file attributes or later:

NOTE: Install the Wininet.dll file on the Server.

NOTE: This QFE needs to applied on top of Internet Explorer 4.0 Service Pack 1.



WORKAROUND
You can also use one of the following workarounds to resolve this issue:
 * Enable Anonymous authentication on the Proxy Server computer.
 * Use the Microsoft Proxy Client.
 * Create an account on the domain using the same username/password as the credentials that you are using for the FTP server that you are trying to get to and give it access permissions to use the proxy.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Keywords: kbbug kbqfe kbpending kbhotfixserver KB222561

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