telnetd(1M) TCP/IP 5.4.2 telnetd(1M)
NAME
telnetd - DARPA TELNET protocol server
SYNOPSIS
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 for a client,
then creating a login process which has the slave side of the pseudo-
terminal as its standard input, output, and error. 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 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 and the X window size is placed in its
stty settings.
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), inetd.conf(4M).
Postel, Jon, and Joyce Reynolds, ``Telnet Protocol Specification,''
RFC 854, Network Information Center, SRI International, Menlo Park,
Calif., May 1983.
NOTES
telnetd has been reimplemented in STREAMS for improved performance.
This means that TELNET must be configured into the kernel through the
system file resulting in a /dev/telnet file. Also, the
/etc/inetd.conf entry for TELNET must have "tli" in the type column,
not "stream" [see inetd.conf(4M)].
Some TELNET commands are only partially implemented.
The TELNET protocol uses the Negotiate About Window Size protocol
sequence to allow for the exchange of the number of lines and columns
on the user's terminal.
Binary mode has no common interpretation except between similar
operating systems.
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telnetd(1M) TCP/IP 5.4.2 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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