Microsoft KB Archive/867755

= Content in Web pages does not appear as expected, or you receive script error messages, after you turn on dynamic HTTP compression for Web sites that use ISAPI filters in Internet Information Services 6.0 =

Article ID: 867755

Article Last Modified on 12/3/2007

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APPLIES TO


 * Microsoft Internet Information Services 6.0

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SYMPTOMS
When you turn on HTTP compression for dynamic content in Web sites in Microsoft Internet Information Services (IIS) 6.0, you may experience unexpected behavior when you browse Web sites that use an Internet Server API (ISAPI) filter. This problem occurs if the following conditions are true:
 * The ISAPI filter registers for the SF_NOTIFY_SEND_RAW_DATA notification and optionally registers for the SF_NOTIFY_SEND_RESPONSE notification.
 * The ISAPI Filter buffers the response in the SF_NOTIFY_SEND_RAW_DATA notification and then reinterprets the buffered response to determine whether the response is chunked.

The symptoms that you experience include one or more of the following:  Content in Web pages does not appear as expected, or you receive script error messages. If you are running Microsoft Content Management Server (MCMS) 2002, you receive JavaScript error messages that are similar to the following:

'NRCOMPAREFROM' is undefined





CAUSE
This problem occurs if the following conditions are true, in the order that they are presented:
 * 1) IIS detects that dynamic compression applies to the response data and then adds the following header fields, as needed:
 * 2) * Content-Encoding
 * 3) * Vary
 * 4) * Transfer-Encoding
 * 5) IIS notifies the SF_NOTIFY_SEND_RESPONSE filters. The SF_NOTIFY_SEND_RESPONSE filters detect the headers that IIS added.
 * 6) IIS starts to send the response and calls the SF_NOTIFY_SEND_RAW_DATA filters.
 * 7) The response is compressed, is chunked, and then is sent to the client.

IIS adds compression headers to the response in step 1. However, the data is not actually modified until step 4. Therefore, when the filter tries to reinterpret the response, filter events that occur between step 1 and step 4 notice that inconsistencies exist between the headers and the body of the response. The headers indicate that the response contains compressed and chunked data. However, the body of the response may or may not be compressed or chunked.



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

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

Prerequisites
No prerequisites are required.

Restart requirement
Stop IIS before you apply this hotfix, and then restart IIS after you apply this hotfix.

Note To stop IIS, click Start, click Run, type net stop w3svc in the Open box, and then click OK.

To start IIS after you stop it, click Start, click Run, type net start w3svc in the Open box, and then click OK.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

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 tool in Control Panel.

Windows Server 2003
  Date         Time   Version       Size     File name -  27-Jul-2004  17:41  6.0.3790.196  342,016  W3core.dll

Windows Server 2003, 64-Bit Edition
  Date         Time   Version       Size     File name 27-Jul-2004 17:41  6.0.3790.196  950,784  W3core.dll  IA-64



WORKAROUND
To work around this problem, turn off HTTP compression for dynamic content in IIS 6.0 if the Web sites do not require HTTP compression. For more information about how to configure HTTP compression in IIS 6.0, visit the following Microsoft Web site:

http://technet2.microsoft.com/windowsserver/en/technologies/featured/iis/default.mspx



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Additional query words: iis fix

Keywords: kbbug kbfix kbqfe kbwinserv2003presp1fix kbhotfixserver KB867755

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