Inetd
Inetd is a super server for Unix systems, and is implemented as a daemon , the network - Sockets listening and inquiry on a particular port a preset program (usually even a daemon) starts. It was introduced in version 4.3 of the Berkeley Software Distribution (BSD).
The Inetd daemon always listens to certain network ports that can be set via a configuration file . When a computer from the network establishes a connection to one of these ports, inetd receives the request and forwards all data to the program belonging to the port (Inetd service). After the connection is terminated, the Inetd daemon automatically stops the service again.
The corresponding server service is only started on request, which saves system resources on the server system for services that are not used frequently . On the other hand, the client has to wait longer for the request because - in contrast to a pure daemon - the response times are significantly longer.
For several years there has been a further developed and newer version of the program called xinetd .
Examples
The following services are often used with inetd instead of starting their own daemons: