The basic configuration files, the kernel configuration file, the startup files, and the /etc/inetd.conf file are necessary for installing the TCP/IP software on a UNIX system, but they require little attention from the system administrator. The kernel comes configured to run TCP/IP on most systems. Some systems, such as Solaris, are designed to eliminate kernel configuration. Others, such as Linux, encourage it as a way to produce a more efficient kernel. In either case, the only thing a network administrator needs to be aware of are the kernel configuration commands required for TCP/IP so that they are not accidentally removed from the kernel when it is rebuilt.
inetd starts essential system services. You would reconfigure only to add new services or to improve security. Security can be improved by removing unneeded services or by adding access control.
The kernel configuration defined the network interface. In Chapter 6 we configure it, calling upon the planning we did in Chapter 4.