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inetd, the Internet services daemon, is normally run at boot time by the /etc/rc.local script. When started inetd reads its configuration information from configuration-file, the default being /etc/inetd.conf. See inetd.conf.5 for more information on the format of this file. It listens for connections on the Internet addresses of the services that its configuration file specifies. When a connection is found, it invokes the server daemon specified by that configuration file for the service requested. Once a server is finished, inetd continues to listen on the socket (except in some cases which will be described below).
Depending on the value of the ``wait-status'' field in the configuration line for the service, inetd will either wait for the server to complete before continuing to listen on the socket, or immediately continue to listen on the socket. If the server is a ``single-threaded'' datagram server (a ``wait-status'' field of ``wait''), inetd must wait. That server will handle all datagrams on the socket. All other servers (stream and ×lti-threaded'' data-gram, a ``wait-status'' field of ``nowait'') operate on separate sockets from the connection request socket, thus freeing the listening socket for new connection requests.
Rather than having several daemon processes with sparsely distributed requests each running concurrently, inetd reduces the load on the system by invoking Internet servers only as they are needed.
inetd itself provides a number of simple TCP-based services. These include echo, discard, chargen (character generator), daytime (human readable time), and time (machine readable time, in the form of the number of seconds since midnight, January 1, 1900). For details of these services, consult the appropriate RFC, as listed below, from the Network Information Center.
inetd rereads its configuration file whenever it receives a hangup signal, SIGHUP. New services can be activated, and existing services deleted or modified in between whenever the file is reread.
Postel, Jon, Echo Protocol, RFC 862, Network Information Center, SRI International, Menlo Park, Calif., May 1983.
Postel, Jon, Discard Protocol, RFC 863, Network Information Center, SRI International, Menlo Park, Calif., May 1983.
Postel, Jon, Character Generator Protocol, RFC 864, Network Information Center, SRI International, Menlo Park, Calif., May 1983.
Postel, Jon, Daytime Protocol, RFC 867, Network Information Center, SRI International, Menlo Park, Calif., May 1983.
Postel, Jon, and Ken Harrenstien, Time Protocol, RFC 868, Network Information Center, SRI International, Menlo Park, Calif., May 1983.
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Created by unroff & hp-tools. © somebody (See intro for details). All Rights Reserved. Last modified 11/5/97