How to specify additional document types for HTTP compression

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Microsoft Internet Information Services (IIS) versions 5.0 and later support HTTP compression as defined in the HTTP specification. By default, HTTP compression only compresses files with a file name extension of "htm," "html," and "txt." This article explains how to specify additional document types for compression.

Note The first Microsoft Exchange Server version that natively supports HTTP compression is Exchange Server 2003. For additional information how to enable HTTP compression in Exchange Server 2003, click the following article number to view the article in the Microsoft Knowledge Base:
830827 How to manage Outlook Web Access features in Exchange Server 2003

Add New Document Types

To add the document types for Microsoft Word, Microsoft PowerPoint, and Microsoft Excel to the default list of documents and restart the IIS services, follow these steps:

NOTE: The commands in step 3 replace the previously defined file extensions. It does not append them to the existing file extensions.
  1. Open a command prompt session. To do this, click Start, click Run, type CMD, and the click OK.
  2. Change the directory to your \InetPub\AdminScripts folder. To do this, type CD \Inetpub\AdminScripts, and then press ENTER.
  3. Type the following commands:
    CSCRIPT.EXE ADSUTIL.VBS SET W3Svc/Filters/Compression/GZIP/HcFileExtensions "htm" "html" "txt" "doc" "ppt" "xls"
    CSCRIPT.EXE ADSUTIL.VBS SET W3Svc/Filters/Compression/DEFLATE/HcFileExtensions "htm" "html" "txt" "doc" "ppt" "xls"
    IISRESET.EXE  (this will reset Web services)
  4. Close the command prompt session.


For more information about compression formats, visit the following Web sites:
RFC 1945 (Hypertext Transfer Protocol -- HTTP/1.0)

RFC 1951 (DEFLATE Compressed Data Format Specification version 1.3)

RFC 1952 (GZIP file format specification version 4.3)

RFC 2616 (Hypertext Transfer Protocol -- HTTP/1.1)


Article ID: 234497 - Last Review: February 28, 2014 - Revision: 5.3
  • Microsoft Internet Information Services 5.0
  • Microsoft Internet Information Services 6.0
kbnosurvey kbarchive kbhowto KB234497

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