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Welcome to a new networking tutorial, based upon the most common technology - TCP/IP over Ethernet. Many of the principles will apply to other technologies, but for now I'm aiming for the simple, rather than totally complete, approach. Just what you need to know to get the job done.

This tutorial is OS-neutral; it uses Linux, Windows and Unix in its examples, but to be honest, those are small details. How TCP/IP works over Ethernet is the same regardless of the OS.

This tutorial skips a lot of the detail which could be written; It is aimed at the new student of TCP/IP who wants to understand how data actually gets from one machine to another over the network. That is not to say that it is a trivial, high-level tutorial. The goal is that the reader should learn the following information by the end of the tutorial:

• How IP networks are structured
• How data is labelled and sent around LANs
• How data is routed from one network to another, and
• How that routing is determined

I intend to keep adding to the tutorial over time; please let me know what you want. There is certainly a lot more detail to be dealt with, but I do want to ensure that the text is kept clear. That is more important than dealing with esoteric issues.

For example, I vow never to mention the OSI 7-layer model. Nobody uses it, yet every networking book starts by explaining what it is.

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In this tutorial, we will imagine a small configuration with a few dedicated servers (machines) on a few different networks. We will start with a single network and by the end of the tutorial, will have built up to the multiple networks shown here.

Don't be put off if the diagram looks small and therefore trivial; This small network diagram provides plenty of detail to get our teeth into.