Many trade books about TCP/IP and the Internet are available from your local library or computer bookstore. The following two books are considered the classic texts on TCP/IP:
Craig Hunt. TCP/IP Network Administration – This book contains some theory and much practical information for managing a heterogeneous TCP/IP network.
W. Richard Stevens. TCP/IP Illustrated, Volume I – This book is an in-depth explanation of the TCP/IP protocols. This book is ideal for network administrators who require a technical background in TCP/IP and for network programmers.