netcat creates a TCP socket either in listening mode (server socket) or a socket that is used in order to connect to a server (client mode). Actually, netcat does not care whether the socket is meant to be a server or a client. All it does is to take the
Unix command-line utility netcat gets called the "network swiss army knife" with good reason. Like the best UNIX utilities, it's very simple but can perform all sorts of useful tasks.