Cisco Certified Network Associate (CCNA) Practice Exam

What TCP port does Telnet utilize?

1. TCP 21

2. TCP 23

3. TCP 25

4. TCP 80

The correct answer is: TCP 23

Telnet utilizes TCP port 23 for its operations. This protocol is designed for providing a command-line interface for communication with a remote device or server over a network. It enables users to log into remote systems and execute commands as if they were physically present at the terminal. The choice of TCP port 23 is standardized for Telnet services, making it possible for applications and devices that implement Telnet to use this port for connections, ensuring consistency across different systems and networks. When establishing a Telnet session, the client attempts to connect to the server on this port, allowing for the expected behavior and communication between devices utilizing the Telnet protocol. Other ports listed, such as TCP 21 (used for FTP), TCP 25 (used for SMTP), and TCP 80 (used for HTTP), serve different protocols and purposes, and therefore are not applicable for Telnet connections.