Short description of IP2Location ISAPI Filter 1.3: IP2Location ISAPI Filter is an Internet Server Application Programming Interface (ISAPI) plug-in that can be used with any web server running IIS, which enables you to discover in real-time, where your web visitors are coming from by IP address. You can determine what country they are by IP address. IP2Location ISAPI Filter used server variable dynamically tailor the content of your site.