4.2BSD/usr/man/man8/telnetd.8c

.TH TELNETD 8C "4 March 1983"
.UC 4
.SH NAME
telnetd \- DARPA TELNET protocol server
.SH SYNOPSIS
.B /etc/telnetd
[
.B \-d
] [
.I port
]
.SH DESCRIPTION
.I 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
.IR services (5).
This port number may be overridden (for debugging purposes)
by specifying a port number on the command line.  If the
.B \-d
option is specified, each socket created by
.I telnetd
will have debugging enabled (see SO_DEBUG in
.IR socket (2)).
.PP
.I Telnetd
operates by allocating a pseudo-terminal device (see
.IR pty (4))
for a client, then creating a login process which has
the slave side of the pseudo-terminal as 
.BR stdin ,
.BR stdout ,
and
.BR stderr .
.I Telnetd
manipulates the master side of the pseudo terminal,
implementing the TELNET protocol and passing characters
between the client and login process.
.PP
When a TELNET session is started up, 
.I telnetd
sends a TELNET option to the client side indicating
a willingness to do ``remote echo'' of characters.
The pseudo terminal allocated to the client is configured
to operate in ``cooked'' mode, and with XTABS and CRMOD
enabled (see
.IR tty (4)).
Aside from this initial setup, the only mode changes
.I telnetd
will carry out are those required for echoing characters
at the client side of the connection.
.PP
.I 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.
.SH "SEE ALSO"
telnet(1C)
.SH BUGS
A complete list of the options supported should be given here.