When any web browser connects to a remote web server it presents its User Agent string. The user agent string gives information
about the browser and operating system. This information winds up in the web
servers access log. If you have a firewall at work with a proxy server for web
browsing, the user agent string is used to determine if your browser is an
approved version. An example:
MSIE 5.5; Windows NT 4.0)
The following registry hack lets you
control the User Agent string.
Key: SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\User
The Post Platform key may have several values. These
values make up the user agent string. To prevent this info from being spread
around the Internet, delete the values under this key.