Web Server Compression

Web Server Compression Modules

Why compress content?

It is recommended that high-use sites implement a Web Server compression module. These are freely available for both Apache (Unix/Linux/Windows) and IIS (Windows), and have a significant impact on cost and bandwidth reduction, as well as increasing download speeds for end-users.

How will this affect my server?

Most browsers understand compressed (sometimes called "zipped") content. Fortunately, the server will not send compressed content to those browsers that cannot accept it. You should note however that compressing the content does have a slight overhead on the server, as it needs to compress it before sending it to you.

Note that only textual (e.g. HTML and CSS) content should be compressed, as image files (e.g. GIF and JPEG) are already compressed and are not likely to result in any space savings if you try to compress them again.

Testing for Compression module

To test whether your site has such a module enabled, go to http://leknor.com/code/gziped.php?url=http%3A%2F%2Fwww.govt.nz

Examples of such modules can be found at:

http://www.pipeboost.com/ for IIS (Microsoft's web server)

http://httpd.apache.org/docs/2.0/mod/mod_deflate.html for Apache Web server

Both these modules use the underlying compression library zlib.