inetd(8)

NAME
     inetd - internet ``super-server''

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

DESCRIPTION
     Inetd is run at boot time by /usr/etc/rc.  It 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.  There must be an entry for each  field,  except
     as noted below.  The fields of the configuration file are as follows:

             service name
             socket type
             protocol
             wait/nowait
             user
             server program
             [ program number ] if service name is ``sunrpc''
             [ version ]             if service name is ``sunrpc''
             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''  (``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''.

     If the service name is ``sunrpc'', two additional  fields  are  required:
     The  first,  program  number,  is  the  well-known  Remote Procedure Call
     program number.  The second, version, is the version number or  range  of
     versions  served  by  the  server  program.   A  version range is a dash-
     separated pair of numbers.

     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.

FILES
     /etc/inetd.conf /etc/services /etc/protocols

SEE ALSO
     comsat(8), ftpd(8), rexecd(8), rlogind(8), rshd(8), telnetd(8), tftpd(8).

BUGS
     The Minix-vmd port of inetd only supports stream type services as of yet.