Microsoft KB Archive/312864

= Automatic Proxy Discovery in Internet Explorer with DHCP requires specific permissions =

Article ID: 312864

Article Last Modified on 8/29/2007

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APPLIES TO

 Microsoft Internet Explorer 6.0, when used with:  Microsoft Windows XP Professional

 Microsoft Windows 2000 Standard Edition 

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This article was previously published under Q312864





SYMPTOMS
You can configure Internet Explorer to use the Automatic Proxy Discovery functionality over Dynamic Host Configuration Protocol (DHCP). This option can direct Web clients to ISA Server's Web proxy service through Web Proxy Autodetect (WPAD) process. In Microsoft Windows 2000, this feature works only for users who are member of the Administrators or Power Users group. In Microsoft Windows XP, the Network Configuration Operators group also has permission to issue DHCP queries.



CAUSE
DHCP client calls are implemented over a RAW named pipe. For security reasons, specific permissions are set on the named pipe. In Windows 2000, an access control entry (ACE) is set on the pipe for the Administrators and Power Users groups. In Windows XP, an ACE is also set for the Network Configuration Operators group.

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Hotfix information
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 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 tool in Control Panel. <pre class="fixed_text">  Date         Time   Version            Size    File name --  08-Jul-2003  01:27  5.0.2195.6770      89,360  Dhcpcsvc.dll

Service pack information
To resolve this problem, obtain the latest service pack for Windows XP. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

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

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

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

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 tool in Control Panel. <pre class="fixed_text">  Date         Time   Version            Size    File name --  29-Mar-2004  09:20  5.1.2600.1351     103,936  Dhcpcsvc.dll

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WORKAROUND
To work around this behavior, use one of the following methods:
 * Make sure that the appropriate user belongs to one of the groups that are listed in the &quot;Symptoms&quot; section of this article.
 * Use an automatic configuration script instead of Automatic Proxy Discovery.

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STATUS
This behavior is by design. This problem was corrected in Microsoft Windows XP Service Pack 2.

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MORE INFORMATION
For more information about how to configure Automatic Proxy Discovery, click the following article number to view the article in the Microsoft Knowledge Base:

252898 How to enable Proxy Autodiscovery in Windows 2000

Additional query words: WPAD Proxy Autodiscovery dhcpinform

Keywords: kbhotfixserver kbqfe kbenv kbfix kbprb KB312864

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