Computer Network:TELNET protocol and TELNET command.

Object: Study TELNET protocol. How you use TELNET program for interactive session with a remote host.

Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. Through Telnet, an administrator or another user can access someone else's computer remotely.

Telnet offers users the capability of running programs remotely and facilitates remote administration. Telnet is available for practically all operating systems and eases integration in heterogeneous networking environments.Telnet is best understood in the context of a user with a simple terminal using the local Telnet program (known as the client program) to run a logon session on a remote computer where the user's communications needs are handled by a Telnet server program. 

It should be emphasized that the Telnet server can pass on the data it has received from the client to many other types of processes including a remote logon server. Communication is established using TCP/IP and is based on a Network Virtual Terminal (NVT). On the client, the Telnet program is responsible for translating incoming NVT codes to codes understood by the client's display device as well as for translating client-generated keyboard codes into outgoing NVT codes.

Syntax

Telnet [host [port]]

host	Specifies the hostname or IP address of the remote computer to connect to.
port	Specifies the port number or service name.

close	close current connection
display	display operating parameters
open	connect to a site
quit	exit telnet
set	set options (type 'set ?' for a list)
status	print status information
unset	unset options (type 'unset ?' for a list)
?/help	print help information