{{Short description|Type of daemon generally run on Unix-like systems}} thumb|upright=1.9|Principle of super-server [[File:Superserver 2.svg|thumb|upright=1.9|Example of a server running sshd (port 22), identd (port 113), ftpd (port 21) and httpd (port 80)]] A '''super-server''', sometimes called a '''service dispatcher''', is a type of daemon run generally on Unix-like systems.
== Usage == A super-server starts other servers when needed, normally with access to them checked by a TCP wrapper. It uses very few resources when in idle state. This can be ideal for workstations used for local web development, client/server development{{cn|date=July 2017}} or low-traffic daemons with occasional usage (such as ident and SSH).
== Performance == The creation of an operating system process embodying the sub-daemon is deferred until an incoming connection for the sub-daemon arrives. This results in a delay to the handling of the connection (in comparison to a connection handled by an already-running process).
Whether this delay is incurred repeatedly for every incoming connection depends on the design of the particular sub-daemon; simple daemons usually require a separate sub-daemon instance (i.e. a distinct, separate operating system process) be started for each and every incoming connection. Such a request-per-process design is more straightforward to implement, but for some workloads, the extra CPU and memory overhead of starting multiple operating system processes may be undesirable.
Alternatively, a single sub-daemon operating system process can be designed to handle multiple connections, allowing similar performance to a "stand alone" server (except for the one-off delay for the first connection to the sub-daemon).<ref>{{cite web |last1=Lennart |first1=Poettering |title=systemd for Developers I |url=http://0pointer.net/blog/projects/socket-activation.html |website=Pid Eins |access-date=26 April 2021}}</ref>
== Implementations == * inetd * launchd * systemd * ucspi-tcp * xinetd
==References== {{reflist}}
{{Network-software-stub}}
Category:Internet Protocol based network software Category:Servers (computing)