The main purpose of DNS is to convert easy-to-remember names into the harder-toremember numbers that computers require. On smaller networks, it is typical, and perfectly acceptable, to rely on the DNS servers supplied by your Internet service provider. However, in larger installations, a site should provide some level of DNS service by hosting the service in-house.
Furthermore, it may be necessary to host DNS internally because of the high number of services that rely on a functioning DNS. Of the 23 services listed in Server Admin, Directory Services, Kerberos, and email require fully functioning DNS, while the rest of the services benefit from having DNS available.
For example, the web service will answer requests made by a straight IP address, but the HTTP v1.1 protocol can access and serve different websites from the same IP address, based on the DNS name passed to it. All these considerations require a system administrator to fully understand DNS and to provide a reliable, secure, and accurate DNS service.
The graphical configuration tools for DNS provided in Server Admin have never exposed the full spectrum of options available, forcing anyone with advanced configuration needs to use the command line. In the past, using the command line typically meant that you could not go back to using the graphical user interface tool. However, Leopard removes that limitation by allowing a mix of styles.