HTTP Compression Methods and Files Used by IIS 5.0 (255951)


The information in this article applies to:

  • Microsoft Internet Information Services 5.0
This article was previously published under Q255951

SUMMARY

By default, Internet Information Services (IIS) 5.0 uses the GZip and Deflate HTTP compression methods. Both compression methods are implemented through an ISAPI filter.

MORE INFORMATION

ISAPI Filter

HTTP compression is a subservice of IIS, which is handled through an ISAPI filter. Because this filter is installed at the WWW Service level, compression must be configured for the entire Web server. It cannot be configured for a specific Web site. The following two files handle this compression (located in the %WinDir%\System32\INETSERV folder):
  • CompFilt.dll
  • GZIP.dll

Compression Methods

  • GZIP file format specification - RFC 1952
  • DEFLATE Compressed Data Format Specification - RFC 1951
Note: To look up an RFC, see http://www.ietf.org

For more information on enabling HTTP compression, review the Internet Information Services documentation.
Modification Type:MinorLast Reviewed:7/13/2004
Keywords:kbinfo KB255951
©2004 Microsoft Corporation. All rights reserved.