libprotoident

Libprotoident is a library that performs application layer protocol identification for flows. Unlike many techniques that require capturing the entire packet payload, only the first four bytes of payload sent in each direction, the size of the first payload-bearing packet in each direction and the TCP or UDP port numbers for the flow are used by libprotoident. Libprotoident features a very simple API that is easy to use, enabling developers to quickly write code that can make use of the protocol identification rules present in the library without needing to know anything about the applications they are trying to identify.