Super-server

A super-server or sometimes called a service dispatcher is a type of daemon run generally on Unix-like systems.

A super-server starts other servers when needed, normally with access to them checked by a TCP wrapper.

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).

Principle of super-server
Example of a server running sshd (port 22), identd (port 113), ftpd (port 21) and httpd (port 80).