INETD(8)                             BSD                              INETD(8)



NAME
     inetd - internet "super-server"

SYNOPSIS
     /etc/inetd [ -d ] [ configuration file ]

DESCRIPTION
     The inetd server should be run at boot time by /etc/rc.local.  It then
     listens for connections on certain internet sockets.  When a connection
     is found on one of its sockets, it decides what service the socket
     corresponds to, and invokes a program to service the request.  After the
     program is finished, it continues to listen on the socket (except in some
     cases which will be described below).  Essentially, inetd allows running
     one daemon to invoke several others, reducing load on the system.

     Upon execution, inetd reads its configuration information from a
     configuration file which, by default, is /etc/inetd.conf.  There must be
     an entry for each field of the configuration file, with entries for each
     field separated by a tab or a space.  Comments are denoted by a "#" at
     the beginning of a line.  The fields of the configuration file are as
     follows:
          service name
          socket type
          protocol
          wait/nowait
          user
          server program
          server program arguments

     The service name entry is the name of a valid service in the file
     /etc/services/.  For "internal" services (discussed below), the service
     name must be the official name of the service (that is, the first entry
     in /etc/services).

     The socket type should be one of stream, dgram, qraw, rdm, or seqpacket,
     depending on whether the socket is a stream, datagram, raw, reliably
     delivered message, or sequenced packet socket.

     The protocol must be a valid protocol as given in /etc/protocols.
     Examples might be tcp or udp.

     The wait/nowait entry is applicable to datagram sockets only (other
     sockets should have a nowait entry in this space).  If a datagram server
     connects to its peer, freeing the socket so inetd can received further
     messages on the socket, it is said to be a "multi-threaded" server, and
     should use the nowait entry.  For datagram servers which process all
     incoming datagrams on a socket and eventually time out, the server is
     said to be "single-threaded" and should use a wait entry. comsat (biff)
     and talk are both examples of the latter type of datagram server.  tftpd
     is an exception; it is a datagram server that establishes pseudo-
     connections.  It must be listed as wait in order to avoid a race; the
     server reads the first packet, creates a new socket, and then forks and
     exits to allow inetd to check for new service requests to spawn new
     servers.

     The user entry should contain the user name of the user as whom the
     server should run.  This allows for servers to be given less permission
     than root.  The server program entry should contain the pathname of the
     program which is to be executed by inetd when a request is found on its
     socket.  If inetd provides this service internally, this entry should be
     internal.

     The arguments to the server program should be just as they normally are,
     starting with argv[0], which is the name of the program.  If the service
     is provided internally, the word internal should take the place of this
     entry.

     inetd provides several "trivial" services internally by use of routines
     within itself.  These services are 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).  All of these services are tcp based.  For details of these
     services, consult the appropriate RFC from the Network Information
     Center.

     inetd rereads its configuration file when it receives a hangup signal,
     SIGHUP.  Services may be added, deleted or modified when the
     configuration file is reread.

SEE ALSO
     comsat(8C), ftpd(8C), rexecd(8C), rlogind(8C), rshd(8C), telnetd(8C),
     tftpd(8C);
     Configuring and Managing TCP/IP.