Question

Explain the working of TELNET.

Answer 1

TELNET: TELNET is an abbreviation for TErminaLNETwork. It is the standard TCP/IP protocol for virtual terminal service.

TELNET Working: * TELNET is a client-server application that allows a user to log on to a remote machine, giving the user access to the remote system. * The user sends the keystrokes to the terminal driver, where the local operating system accepts the characters but does not interpret them. * A terminal driver correctly interprets the keystrokes on the local terminal or terminal emulator. * The characters are sent to the TELNET client, which transforms the characters to a universal character set called network virtual terminal (NVT) characters and delivers them to the local TCP/IP protocol stack. * The commands or text, in NVT form, travel through the Internet and arrive at the TCP/IP stack at the remote machine. * 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. * 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: It is designed to receive characters from a terminal driver. * A piece of software called a pseudo terminal driver is added which pretends that the characters are coming from a terminal. * The operating system then passes the characters to the appropriate application program. 

Fig. Working of TELNET