TELNETD(1M)                                           TELNETD(1M)



     NAME
          telnetd - DARPA TELNET protocol server

     SYNOPSIS
          /etc/telnetd

     DESCRIPTION
          Telnetd is a server which supports the DARPA standard TELNET
          virtual terminal protocol.  Telnetd is invoked by the
          internet server (see inetd(1m)), normally for requests to
          connect to the TELNET port as indicated by the /etc/services
          file (see services(4)).

          Telnetd operates by allocating a pseudo-terminal device (see
          pty(7)) 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 protocol and
          passing characters between the remote client and the login
          process.

          When a TELNET session is started up, telnetd sends TELNET
          options to the client side indicating a willingness to do
          remote echo of characters, to suppress go ahead, and to
          receive terminal type information from the remote client.
          If the remote client is willing, the remote terminal type is
          propagated in the environment of the created login process.
          The pseudo-terminal allocated to the client is configured to
          operate in "cooked" mode, and with XTABS and CRMOD enabled
          (see termio(7)).

          Telnetd is willing to do:  echo, binary, suppress go ahead,
          and timing mark.  Telnetd is willing to have the remote
          client do:  binary, terminal type, and suppress go ahead.

     SEE ALSO
          telnet(1C)

     BUGS
          Some TELNET commands are only partially implemented.

          The TELNET protocol allows for the exchange of the number of
          lines and columns on the user's terminal, but telnetd
          doesn't make use of them.

          Because of bugs in the original 4.2 BSD telnet(1C), telnetd
          performs some dubious protocol exchanges to try to discover
          if the remote client is, in fact, a 4.2 BSD telnet(1C).

          Binary mode has no common interpretation except between
          similar operating systems (Unix in this case).




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     TELNETD(1M)                                           TELNETD(1M)



          The terminal type name received from the remote client is
          converted to lower case.

          The packet interface to the pseudo-terminal (see pty(7))
          should be used for more intelligent flushing of input and
          output queues.

          Telnetd never sends TELNET go ahead commands.

     ORIGIN
          4.3 BSD












































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