INETD(8)                386BSD System Manager's Manual                INETD(8)

NAME
     inetd - internet ``super-server''

SYNOPSIS
     inetd [-d] [configuration file]

DESCRIPTION
     Inetd should be run at boot time by /etc/rc.local (see rc(8)).  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.

     The option available for inetd:

     -d      Turns on debugging.

     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.  There must be an entry for each field.  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'', ``raw'', ``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(8) (biff(1))  and talkd(8) are both examples of the latter type of
     datagram server.  Tftpd(8) 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 server program arguments should be just as arguments 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(8),  fingerd(8),  ftpd(8),  rexecd(8),  rlogind(8),  rshd(8),
     telnetd(8),  tftpd(8)

HISTORY
     The inetd command appeared in 4.3BSD.

4.3 Berkeley Distribution       March 16, 1991                               2