Telnet

Telnet is a network protocol used for accessing remote computers. It allows users to connect to a server or a device over a network and execute commands as if they were directly connected to the machine. Created in 1969, Telnet was one of the earliest protocols developed for the Internet and was primarily used by system administrators and developers.

Developed by researchers at Bolt, Beranek, and Newman (BBN) for the ARPANET, the precursor to the modern Internet, Telnet was designed to facilitate remote computing. Essentially, it allows for bi-directional, text-based communication between two machines, typically a client and a server. By default, Telnet operates over TCP port 23, though it can be configured to use other ports. Despite its pioneering role, Telnet has significant security drawbacks. It transmits data, including usernames and passwords, in plain text, making it vulnerable to interception and eavesdropping. Consequently, Telnet has largely been replaced by more secure protocols such as Secure Shell (SSH), which encrypts the entire communication session. However, Telnet is still used in some controlled environments and for troubleshooting network issues. Its legacy continues to be a fundamental piece of networking history and understanding basic networking concepts.