Cisco Certified Network Associate (CCNA) Practice Exam

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Study for the Cisco Certified Network Associate (CCNA) exam with our comprehensive quiz featuring multiple-choice questions and detailed explanations. Prepare effectively and enhance your understanding of networking concepts!

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Which TCP port is designated for FTP control commands?

  1. 20

  2. 21

  3. 23

  4. 25

The correct answer is: 21

The designated TCP port for FTP (File Transfer Protocol) control commands is 21. FTP operates using a client-server model, where the control commands are sent over this port to establish and manage the connection between the client and server. When a user initiates an FTP session, the control information, such as login credentials and commands to transfer files, is transmitted over this port. In addition, port 20 is commonly associated with FTP data transfer, but it is specifically used for the active mode data transfer, not for control commands. Port 23 is designated for Telnet, which is used for remote command-line access, while port 25 is reserved for SMTP (Simple Mail Transfer Protocol), used for email transmission. Understanding the roles of these ports is essential for managing network communications effectively.

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