UrlScan v3.1 can be set up as either a global filter or a site level filter. The default installation will install Urlscan as a global Filter only. The site filter is required to be the highest priority filter for it to function properly. Upgrade to v2.5 or Url scan v3.0 will leave your old.ini file intact. Use the “Site Filter” folder to set up your filter as a site filter for this purpose. For IIS 6.0 and 7.0 make sure you give IIS_WPG write permissions to this folder.”]
Source: https://docs.microsoft.com/en-us/iis/extensions/working-with-urlscan/urlscan-setup