What protocol provides command-line access from one host to another in a network?

The protocol that provides command-line access from one host to another in a network is Telnet. It is a network protocol used to provide a command-line interface for communication with a remote device. Telnet operates over TCP and allows users to establish a session with a remote server or device, typically on port 23. This allows for the management or configuration of network devices and servers through a terminal interface.

However, it is essential to note that Telnet transmits data in plain text, making it vulnerable to interception and unauthorized access, which is a significant security risk. Because of these vulnerabilities, more secure alternatives like SSH (Secure Shell) have become preferred for remote access, as SSH encrypts the data transmitted over the network, providing a secure and safe connection.

Thus, while Telnet is indeed a command-line access protocol, the choice of SSH is more appropriate in modern practices due to its security advantages. The other protocols like FTP (File Transfer Protocol) and HTTP (Hypertext Transfer Protocol) serve different purposes, primarily file transfer and web communication, and do not facilitate command-line access directly.