

Microsoft later released UrlScan 3.1 as a separate download, which added enhanced parsing of escape sequences in URLs and query strings. UrlScan 3.0 added change notifications for the UrlScan.ini file, so it is no longer necessary to restart IIS after updating your UrlScan.ini file.

This feature helps prevent server attacks that use query strings, such as SQL injection attacks. Microsoft released UrlScan 3.0 as a separate download, which added features to create filtering rules, to always allow specific URLs to bypass UrlScan filtering, and to allow or deny requests that contained user-defined query string elements. If you are using UrlScan 3.0, you should download and install the latest version. UrlScan 3.0 has been replaced by UrlScan 3.1.
