INETD(8)                                                              INETD(8)



NAME
       inetd - internet ‘‘super-server’’

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

DESCRIPTION
       _I_n_e_t_d should be run at boot time by _/_e_t_c_/_r_c_._l_o_c_a_l.  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, _i_n_e_t_d allows running  one
       daemon to invoke several others, reducing load on the system.

       Upon  execution,  _i_n_e_t_d reads its configuration information from a con‐
       figuration file which, by default, is _/_e_t_c_/_i_n_e_t_d_._c_o_n_f.  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 _s_e_r_v_i_c_e _n_a_m_e entry is the name of  a  valid  service  in  the  file
       _/_e_t_c_/_s_e_r_v_i_c_e_s_/.   For ‘‘internal’’ services (discussed below), the ser‐
       vice name _m_u_s_t be the official name of the service (that is, the  first
       entry in _/_e_t_c_/_s_e_r_v_i_c_e_s).

       The  _s_o_c_k_e_t  _t_y_p_e  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 _p_r_o_t_o_c_o_l must be a  valid  protocol  as  given  in  _/_e_t_c_/_p_r_o_t_o_c_o_l_s.
       Examples might be ‘‘tcp’’ or ‘‘udp’’.

       The  _w_a_i_t_/_n_o_w_a_i_t  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 _i_n_e_t_d 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.  _T_f_t_p_d 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  _i_n_e_t_d
       to check for new service requests to spawn new servers.

       The  _u_s_e_r  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 _s_e_r_v_e_r _p_r_o_g_r_a_m entry should contain the pathname of the
       program which is to be executed by _i_n_e_t_d when a request is found on its
       socket.   If  _i_n_e_t_d 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.

       _I_n_e_t_d  provides  several ‘‘trivial’’ services internally by use of rou‐
       tines within itself.  These services are ‘‘echo’’, ‘‘discard’’, ‘‘char‐
       gen’’  (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.

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

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



4.3 Berkeley Distribution        May 26, 1986                         INETD(8)