Which protocol is a secure remote management protocol intended as a replacement for Telnet?

• A. Secure Shell (SSH)
• B. Trivial File Transfer Protocol (TFTP)
• C. Simple Mail Transfer Protocol (SMTP)
• D. File Transfer Protocol (FTP)

Answer: (A)

The key idea is that you need a secure way to manage devices remotely. Telnet sends everything in plaintext, including credentials, which makes it easy for someone to eavesdrop or tamper with the session. Secure Shell provides a secure alternative by establishing an encrypted channel between the client and server for remote login and command execution. It authenticates both ends, typically using public-key cryptography, and protects the confidentiality and integrity of the session. SSH also enables secure file transfers (SFTP or SCP) built on the same secure channel, which is a practical bonus for remote administration. The other protocols shown serve different purposes—TFTP is an insecure file transfer method, SMTP handles email, and FTP is a basic file transfer protocol without built-in strong security—so they aren’t suited as a secure remote management replacement for Telnet.