nDPI is a ntop-maintained superset of the popular OpenDPI library. Released under the GPL license, its goal is to extend the original library by adding new protocols that are otherwise available only on the paid version of OpenDPI. In addition to Unix platforms, we also support Windows, in order to provide you a cross-platform DPI experience. Furthermore, we have modified nDPI do be more suitable for traffic monitoring applications, by disabling specific features that slow down the DPI engine while being them un-necessary for network traffic monitoring. nDPI is used by both ntop and nProbe for adding application-layer detection of protocols, regardless of the port being used. This means that it is possible to both detect known protocols on non-standard ports (e.g. detect http non ports other than 80), and also the opposite (e.g. detect Skype traffic on port 80). This is because nowadays the concept of port=application no longer holds.