telnetd(1M)                                           telnetd(1M)



NAME
     telnetd - supports the DARPA standard TELNET protocol

SYNOPSIS
     in.telnetd

DESCRIPTION
     telnetd is a server that supports the DARPA standard TELNET
     virtual terminal protocol.  The telnetd command is invoked
     by the internet server (described in inetd(1M)), normally
     for requests to connect to the TELNET port as indicated by
     the /etc/services file (see services(4N)).

     The telnetd server operates by allocating a pseudoterminal
     device (described in pty(7)) for a client, then creating a
     login process that has the slave side of the pseudoterminal
     as stdin, stdout, and stderr.  telnetd manipulates the
     master side of the pseudoterminal, 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 pseudoterminal allocated to the client is configured to
     operate in ``cooked'' mode, and with XTABS and CRMOD enabled
     (see tty(4)).

     The telnetd server can perform the following tasks: echo,
     binary, suppress go ahead, and timing mark.  The telnetd
     server can perform the following tasks:  binary, terminal
     type, and suppress go ahead.

LIMITATIONS
     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.

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

     The terminal-type name received from the remote client is
     converted to lowercase.



January 1992                                                    1

telnetd(1M)                                           telnetd(1M)



     The ``packet'' interface to the pseudoterminal (described in
     pty(7)) should be used for more intelligent flushing of
     input and output queues.

     The telnetd command never sends TELNET go ahead commands.

FILES
     /etc/issue
          File, displayed by telnetd, containing information the
          system administrator wants users to see when they log
          in over telnet
     /usr/etc/in.telnetd
          Executable file

SEE ALSO
     inetd(1M)

     telnet(1C) in A/UX Command Reference

     services(4N), pty(7) in A/UX Programmer's Reference



































2                                                    January 1992