A simple test program named
sock is used throughout the book to generate TCP and UDP data. It is used as both a client and server process. Having a test program like this, which is executable from a shell prompt, prevents us from having to write new client and server C programs for each specific feature that we want to examine. Since the purpose of this book is to understand the networking protocols, and not network programming, in this Appendix we only describe the program and its various options.
There are numerous other programs with functionality similar to
sock.Juergen Nickelsen wrote a program named
socketand Dave Yost wrote a program named
sockio.Both contain many similar features. Pieces of the