Ethical Hacking Essentials Practice Test

Which port is used by Telnet for communication?

1. Port 80

2. Port 23

3. Port 443

4. Port 21

The correct answer is: Port 23

Telnet utilizes port 23 for communication, which is designated for this protocol. Telnet is a network protocol used to provide a command-line interface for communication with a remote device or server. When a client wants to connect to a Telnet server, it initiates a connection through port 23, enabling the user to execute commands remotely as if they were local to the system. The choice of port 23 is significant because it has been standard for Telnet for many years, allowing consistency across networking setups. Understanding the specific port used by different protocols is essential for network administration and security practices. Administrators often need to ensure that appropriate ports are open or closed according to policy, especially since Telnet transmits data, including credentials, in plain text, which raises security concerns. Other ports listed serve different protocols: port 80 is used for HTTP, port 443 is for HTTPS (secure HTTP), and port 21 is designated for FTP. Recognizing these distinctions not only helps in configuring networks but also aids in implementing effective security measures.