Every Unix computer that runs TCP/IP has a technique for incorporating the basic transport and IP datagram services into its operating system. This chapter discusses two techniques for incorporating the basic TCP/IP configuration into a Unix system: recompiling the kernel, and loading dynamically linked kernel modules. We'll study these techniques and the role they play in linking TCP/IP and Unix. With this information, you should be able to understand how the vendor builds the basic configuration and how to modify it to create your own custom configuration.
The transport and datagram services installed in the operating system are used by the application services described in Chapter 3. There are two different techniques for starting application services: they are either run at boot time or launched on an on-demand basis. This chapter covers both of these techniques and shows you how to configure and control this startup process. But first let's look at how TCP/IP is incorporated into the Unix operating system.