This manual, which is part of the Linux Documentation Project, contains a introduction to the TCP/IP protocols and covers various topics related to configuring networking services.

LAN Administrator's Guide to TCP/IP and routing for Internet-connected LANs.

How do I find the geographical location of a host, given its IP address ?

Technical support forums and mutual help system for computer professionals.

This free electronic book in html format covers not only the TCP/IP protocols but also the configuration of most of the applications a network administrator must maintain

TCP/IP Frequently Asked Questions.

Redbooks Technical Manuals from IBM. TCP/IP Tutorial and Technical Overview

Yet another introduction to the TCP/IP Protocols

Redbooks Technical Manuals from IBM. Learning Practical TCP/IP for AIX V3.2/V4.1 Users: Hints and Tips for Debugging and Tuning

Redbooks Technical Manuals from IBM. High-Speed Networking Technology: An Introductory Survey