At its core, Telnet is a client-server protocol used to provide a bidirectional, interactive text-oriented communication facility. It allows a user on a "client" machine to establish a remote session on a "server." Once the connection is established, your keyboard acts as if it were connected directly to the remote terminal. Why is it still used?
Open the Control Panel > Programs > Turn Windows features on or off. Check the box for Telnet Client . Alternatively, run pkgmgr /iu:"TelnetClient" in Command Prompt as an admin.
It cannot be stressed enough: Because it sends everything—including usernames and passwords—in cleartext, anyone with a packet sniffer (like Wireshark) on the same network can intercept your credentials.
Many older network switches, routers, and industrial controllers only support Telnet for configuration. In a closed, secure internal network, this is still a common practice. The Security Catch