i. TELNET is an abbreviation for Terminal Network. It is the standard TCP/IP protocol for virtual terminal service as proposed by ISO.

ii. TELNET enables the establishment of a connection to a remote system in such a way that the local terminal appears to be a terminal at the remote system.

iii. TELNET is a general-purpose client-server application program.

Remote Login:

i. When a user wants to access an application program or utility located on a remote machine, he or she performs remote login.

Here the TELNET client and server programs come into use, the user sends the keystrokes to the terminal driver.

ii. Where the local operating system accepts the characters but does not interpret them.

iii. The characters are sent to the TELNET client, which transforms the characters to a universal

iv. Character set called Network Virtual Terminal (NVT) characters and delivers them to the local TCP/IP stack (see Figure9).

v. The commands or text, in NVT form, travel through the Internet and arrive at the TCP/IP stack at the remote machine.

vi. Here the characters are delivered to the operating system and passed to the TELNET server, which changes the characters to the corresponding characters understandable by the remote computer.

vii. However, the characters cannot be passed directly to the operating system because the remote operating system is not designed to receive characters from a TELNET server:

viii. It is designed to receive characters from a terminal driver.

ix. The solution is to add a piece of software called a pseudo terminal driver, which pretends that the characters are coming from a terminal.

x. The operating system then passes the characters to the appropriate application program.