Users have come to expect and rely on a variety of network services: logging in to a remote system, accessing files stored on a remote system, seeing information from various websites, and so on. High level network operations typically use a hostname to specify a network location, an easy and convenient practice for users. Accordingly, at the most basic level, network operations depend on two essential abilities: translating a hostname to an IP address and determining the route to a desired remote destination.
For this reason, configuring and managing services that handle name resolution and routing will take up a large part of this chapter. After considering these topics in detail, we will also consider other important network services, including DHCP, which is responsible for assigning IP addresses, and the service that synchronizes the current time on the various systems within a network. The final section of the chapter will consider software and techniques for monitoring network status over time.
inetd is another important
network service. It controls many application-specific services (such as
telnet). It is discussed in Section 7.6 in conjunction with the
TCP Wrappers package, because its configuration has a large potential
effect on system security.