xinetd (the Xtended InterNET services Daemon) is a secure replacement for the inetd.
Most services are run using daemons, processes that sits in the background and waits for an incoming request. Every process takes up a certain amount of memory and when the number of services running on a computer grow there can be quite a few processes running. To reduce the number of running services the idea of a super server was born. The super server, such as xinetd, runs and listens on several ports and when a request comes in xinetd start up the corresponding server daemon and forward the request internally to the process. When the connection is closed so is the daemon.
Services that are suitable for this solution is those that are used infrequently, such as chargen, telnet, pop and imap. On workstation computers the ftp service is often run through the xinetd system.