1. Allows low-level manipulation of TCP/IP headers that is impossible for normal programs. Key point: Most programs go through a high-level interface (like sockets) in order to send traffic on the network. Sometimes, for security or hacking reasons, a program needs to construct its own network headers. The existing TCP/IP stack is unable to build these headers, so you must bypass it and go directly to the hardware drivers. Libnet is a library that makes custom packet generation easier. Misunderstanding: Some people believe that libnet will not work on Win95 or WinNT because these systems do not support raw sockets. This is false -- libnet has been widely used on these platforms. From Hacking-Lexicon