Hi All, Interesting question. I am working on a site, which requires IE6. In order to prevent users who work with other browsers from accessing the site I wrote some kind of filter to check the user agent string, and redirect the user to an upgrade-your-browser page. This redirection also causes requests from web-crawlers (search engines) to be redirected to this page. The site contains a lot of content, which I want to be added to the search engines' indexes. Now to the question: How do I identify a request from a web-crawler? Is there a standard header in the HTTP Request to check? I am particularly interested in Google's headers since it is most popular. Thanks in advance, David.