In TCP/IP networking, which protocol specifically provides a remote terminal connection service that lets a user interact with a distant host's command-line session as if locally attached?

Introduction / Context:
Remote terminal access is a classic requirement in computer networks. Within the TCP/IP suite, one protocol was defined expressly to provide interactive, character-based sessions on remote systems. Knowing which protocol offers this “virtual terminal” service helps differentiate it from file transfer, name/address resolution, or transport-only mechanisms.

Given Data / Assumptions:

• The question asks for the TCP/IP protocol that enables interactive remote terminal connections.
• The context is command-line access (character-oriented), not file transfer or background data movement.
• The protocol predates modern secure alternatives but remains historically important.

Concept / Approach:
TELNET provides a Network Virtual Terminal model over TCP. It negotiates options (like echoing) and carries keystrokes and screen output between client and server, giving the user a live shell on the remote host. By contrast, FTP is for file transfer; RARP was for address resolution from MAC to IP on legacy LANs; UDP is a transport protocol, not an application service; SSH is a secure modern replacement but was not the original TCP/IP “remote terminal connection service.”

Step-by-Step Solution:

Verification / Alternative check:
Default port mappings confirm roles: TELNET typically uses TCP port 23, FTP uses TCP ports 21/20, and SSH (a secure replacement) uses TCP port 22. Historical admin practices used TELNET widely before encrypted alternatives became standard.

Why Other Options Are Wrong:

• FTP: transfers files; not an interactive terminal protocol.
• RARP: resolves MAC to IP; unrelated to remote login.
• UDP: transport layer, not a terminal application protocol.
• SSH: provides secure terminal access, but the question asks for the standard TCP/IP remote terminal service—TELNET.

Common Pitfalls:
Assuming any remote shell implies SSH; exam questions often test recognition that TELNET is the classic, non-encrypted terminal protocol.

Final Answer:
TELNET