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Q307633: IIS Does Not Return HTTP 304 Not Modified for Compressed Content

Article: Q307633
Product(s): Internet Information Server
Version(s): 5.0
Operating System(s): 
Keyword(s): kbCOMIS kbWin2000PreSP3Fix kbWin2000sp3fix
Last Modified: 15-AUG-2002

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The information in this article applies to:

- Microsoft Internet Information Services version 5.0 
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SYMPTOMS
========

When you use HTTP compression, Internet Information Services (IIS) sends the
complete HTML page instead of responding with an HTTP status code "304 Not
Modified" message. This occurs even if the HTML page has not been modified.

CAUSE
=====

If a browser includes the length attribute in the GET request, IIS compares the
length of the compressed page with the length that is submitted by the browser.
Because the browser sends the size of the uncompressed page, IIS submits the
page again.

WORKAROUND
==========

Do not use HTTP compression.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Windows 2000. For
additional information, click the following article number to view the article
in the Microsoft Knowledge Base:

  Q260910 How to Obtain the Latest Windows 2000 Service Pack

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

  Date        Time   Version        Size    File name 
  ----------------------------------------------------
  11-Oct-2001 15:16  5.0.2195.43   337,680  Asp.dll
  11-Oct-2001 15:16  5.0.2195.36   299,792  Fscfg.dll
  11-Oct-2001 15:16  5.0.2195.43     8,464  Ftpctrs2.dll
  11-Oct-2001 15:16  5.0.2195.43     6,416  Ftpmib.dll
  11-Oct-2001 15:16  5.0.2195.43     9,488  Httpmib.dll
  11-Oct-2001 15:16  5.0.2195.44    13,584  Infoadmn.dll
  11-Oct-2001 15:16  5.0.2195.44   245,520  Infocomm.dll
  11-Oct-2001 15:16  5.0.2195.44    62,736  Isatq.dll
  30-May-2001 00:03  5.0.2195.36     3,584  Spmsg.dll
  11-Oct-2001 15:16  5.0.2195.43     7,440  W3ctrs.dll
  11-Oct-2001 15:16  5.0.2195.44   348,432  W3svc.dll


STATUS
======

Microsoft has confirmed that this is a problem in IIS 5.0. This problem was
first corrected in Windows 2000 Service Pack 3.

Additional query words: kbIISCom

======================================================================
Keywords          : kbCOMIS kbWin2000PreSP3Fix kbWin2000sp3fix 
Technology        : kbiisSearch kbiis500
Version           : :5.0
Hardware          : x86
Issue type        : kbbug
Solution Type     : kbfix

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