Telnet operates as a client-server protocol, facilitating remote access to computer systems over a network.
Here's a breakdown of how Telnet functions:
-
Client-Server Model: Telnet employs a classic client-server architecture. A Telnet client initiates a connection to a Telnet server.
-
Server Listening: The Telnet server application actively listens for incoming connection requests on a specific port (typically port 23).
-
Connection Establishment: When a Telnet client requests a connection, the server accepts it, establishing a bidirectional communication channel.
-
Command Transmission: The client transmits commands to the server as plain text. These commands are instructions that the client wants the server to execute.
-
Server Response: The Telnet server interprets the commands received from the client and executes them. The server then sends back responses, which can include the results of the commands or error messages.
-
Plain Text Communication: All data transmitted between the client and server is unencrypted plain text. This is a significant security vulnerability.
-
Session Termination: Either the client or the server can terminate the connection, ending the Telnet session.
In essence, Telnet provides a text-based interface to interact with a remote server. Users can log in, run programs, and manage files on the remote machine as if they were directly connected to it. However, due to its lack of encryption, Telnet is considered insecure and is largely replaced by more secure protocols like SSH.
