A super-server or sometimes called a service dispatcher is a type of daemon

Daemon (computer software)

In Unix and other multitasking computer operating systems, a daemon is a computer program that runs as a background process, rather than being under the direct control of an interactive user...

 run generally on Unix-like

Unix-like

A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....

 systems.

Usage

It starts other servers when needed, normally with access to them checked by a TCP wrapper

TCP Wrapper

TCP Wrapper is a host-based networking ACL system, used to filter network access to Internet Protocol servers on operating systems such as Linux or BSD...

. It uses very few resources when in idle state. This can be ideal for workstations used for local web development

Web development

Web development is a broad term for the work involved in developing a web site for the Internet or an intranet . This can include web design, web content development, client liaison, client-side/server-side scripting, web server and network security configuration, and e-commerce development...

, client/server development or low traffic daemons with occasional usage such as ident

Ident

The Ident Protocol, specified in RFC 1413, is an Internet protocol that helps identify the user of a particular TCP connection. One popular daemon program for providing the ident service is identd.-How ident works:...

 and SSH

Secure Shell

Secure Shell is a network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that it connects via a secure channel over an insecure network: a server and a client...

.

Performance

There is a slight delay in connecting to the sub-daemons, thus, when compared to standalone servers, a super-server setup may be less performant, especially when under high load. Some servers, such as hpa-tftpd, therefore take over the internet socket

Internet socket

In computer networking, an Internet socket or network socket is an endpoint of a bidirectional inter-process communication flow across an Internet Protocol-based computer network, such as the Internet....

 and listen on it themselves for some specified interval, anticipating more connections to come.

Implementations

• inetd
  Inetd
  inetd is a super-server daemon on many Unix systems that manages Internet services. First appearing in 4.3BSD , it is generally located at /usr/sbin/inetd.-Function:...
  
  
• launchd
  Launchd
  launchd is a unified, open-source service management framework for starting, stopping and managing daemons, applications, processes, and scripts...
  
  
• systemd
  Systemd
  systemd is a replacement for the System V init daemon for Linux. It is intended to provide a better framework for expressing services' dependencies, allow more work to be done in parallel at system startup, and to reduce shell overhead....
  
  
• ucspi-tcp
  Ucspi-tcp
  ucspi-tcp is a public domain Unix TCP command-line tool for building TCP client-server applications. It consists of super-server tcpserver and tcpclient application....
  
  
• xinetd
  Xinetd
  In computer networking, xinetd, the eXtended InterNET Daemon, is an open-source super-server daemon which runs on many Unix-like systems and manages Internet-based connectivity...