4.1 TCP/IP and OSI

Imagine if you will, a classroom filled with entry-level web technology students. We have some questions from the audience: "What makes up the Internet?" "What is it?" One answer is TCP/IP. "Oh that tells me a lot! It sounds like some kind of drug!" The next question is, "Where should we start and what level of detail should we go into?" The useful answers to these questions will be answered in this chapter.

TCP/IP is a very complex protocol. There are entire books dedicated to the subject. We need to discuss TCP/IP at some length in order to understand the security issues with the protocol. Throughout this chapter, we will list some books and URLs that provide further information on TCP/IP. Most major operating system vendors offer some type of course on TCP/IP. As part of the MCSE program from Microsoft (MCSE 2000 Microsoft Corporation), there is a test that is specifically dedicated to TCP/IP. Please see the references or take a course for a full coverage of TCP/IP. We will start with a high-level overview of TCP and its components and then cover a few security-related issues.

In 1973, Vinton Cerf, a UCLA graduate student who is also known as the "father of the Internet," and Robert Kahn, an MIT math professor, developed a set of software "protocols" to enable different types of computers to exchange data. These protocols are now known as TCP/IP. The base part of the protocol is called IP, or...