With continual advances in hardware and TCP/IP networking capabilities, this very popular book deserves an update. The TCP/IP protocol suite has become the de facto standard for computer communications in today's networked world. The ubiquitous implementation of a specific networking standard has led to an incredible dependence on the applications enabled by it. Today, we use the TCP/IP protocols and the Internet not only for entertainment and information, but to conduct our business by performing transactions, buying and selling products, and delivering services to customers. We are continually extending the set of applications that leverage TCP/IP, thereby driving the need for further infrastructure support. It is our hope that both the novice and the expert will find useful information in this publication.