Using Apache's SetEnvIf Directive to Block Certain Requests From Access Logs

[mandy]

Normally Apache logs all requests in its access log. In certain cases this can distort your page view statistics (if you use a tool like Webalizer or AWStats that creates statistics based on Apache's access log), for example if you get lots of visits from search engine spiders or from a certain IP address (e.g. your own), or if each of your pages includes another page (e.g. in an iframe) from your web site (that would instantly double your page views which is obviously not correct). This short guide shows how you use Apache's SetEnvIf directive to prevent Apache from logging such requests...

full article: http://www.howtoforge.com/setenvif_apache2