.\" Copyright (c) 1983 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)telnetd.8 5.1 (Berkeley) %G%
.TH TELNETD 8C "4 March 1983"
telnetd \- DARPA TELNET protocol server
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;
This port number may be overridden (for debugging purposes)
by specifying a port number on the command line. If the
option is specified, each socket created by
will have debugging enabled (see SO_DEBUG in
operates by allocating a pseudo-terminal device (see
for a client, then creating a login process which has
the slave side of the pseudo-terminal as
manipulates the master side of the pseudo terminal,
implementing the TELNET protocol and passing characters
between the client and login process.
When a TELNET session is started up,
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
Aside from this initial setup, the only mode changes
will carry out are those required for echoing characters
at the client side of the connection.
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
A complete list of the options supported should be given here.