telnetd(1M)							   telnetd(1M)

NAME    [Toc]    [Back]

     telnetd - internet	TELNET protocol	server

SYNOPSIS    [Toc]    [Back]

     /usr/etc/telnetd [	-h ] [ -n ]

DESCRIPTION    [Toc]    [Back]

     telnetd is	a server which supports	the Internet standard TELNET virtual
     terminal protocol.	 telnetd is invoked by the Internet super-server (see
     inetd(1M)), normally for requests to connect to the TELNET	port as
     indicated by the /etc/services file (see services(4)).  The -h option
     suppresses	the host information banner before the login prompt.  The -n
     option suppresses transport-level keep-alive messages.  The use of	keepalive
 messages allows sessions to be timed	out if the client crashes or
     becomes unreachable.

     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,	to do remote flow control, and to receive terminal
     type information, terminal	speed information, and window size 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.

     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, terminal speed, window size,	toggle flow control, environment, X
     display location, and suppress go ahead.  Attempts	to set environment
     variables understood by rld(1) are	ignored	and logged.  Currently,	these
     are LD_LIBRARY_PATH and any variable name starting	with _RLD.

SEE ALSO    [Toc]    [Back]

     telnet(1C).

BUGS    [Toc]    [Back]

     Some TELNET commands are only partially implemented.

     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.

     telnetd never sends TELNET	go ahead commands.


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