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TELNETD(8C)                                                        TELNETD(8C)

       telnetd - DARPA TELNET protocol server

       /etc/telnetd [ -d ] [ port ]

       Telnetd  is  a  server which supports the DARPA standard TELNET virtual
       terminal protocol.  The TELNET server operates at the port indicated in
       the  ``telnet'' service description; see services(5).  This port number
       may be overridden (for debugging purposes) by specifying a port  number
       on  the  command line.  If the -d option is specified, each socket cre-
       ated  by  telnetd  will  have  debugging  enabled  (see   SO_DEBUG   in

       Telnetd  operates  by  allocating a pseudo-terminal device (see pty(4))
       for a client, then creating a login process which has the slave side of
       the  pseudo-terminal as stdin, stdout, and stderr.  Telnetd manipulates
       the master side of the pseudo terminal, implementing the TELNET  proto-
       col and passing characters between the client and login process.

       When  a  TELNET session is started up, telnetd sends a TELNET option to
       the client side indicating a willingness to do ``remote echo'' of char-
       acters.   The  pseudo terminal allocated to the client is configured to
       operate in ``cooked'' mode, and  with  XTABS  and  CRMOD  enabled  (see
       tty(4)).   Aside from this initial setup, the only mode changes telnetd
       will carry out are those required for echoing characters at the  client
       side of the connection.

       Telnetd  supports  binary  mode, and most of the common TELNET options,
       but does not, for instance, support timing marks.  Consult  the  source
       code for an exact list of which options are not implemented.


       A complete list of the options supported should be given here.

4th Berkeley Distribution        4 March 1983                      TELNETD(8C)