Err Msg: HTTP/1.1 407 Proxy Authentication Required

ID: Q222561

The information in this article applies to:

Microsoft Internet Explorer versions 3.02, 4.0, 4.01, 4.01 Service Pack 1, 4.01 Service Pack 2 for Windows 95
Microsoft Proxy Server version 2.0

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 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:

Version File name

4.72.3513.1101 Wininet.dll

Version	File name
4.72.3513.1101	Wininet.dll

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

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 this to be a problem in the Microsoft products listed at the beginning of this article.

Additional query words:


Keywords          : 
Version           : WINDOWS:3.02,4.0,4.01,4.01 Service Pack 1,4.01 Service Pack 2; winnt:2.0
Platform          : WINDOWS winnt 
Issue type        : kbbug

Last Reviewed: July 9, 1999