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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What is the TCP port number used for FTP control communication?

  1. TCP 20

  2. TCP 21

  3. TCP 80

  4. TCP 53

The correct answer is: TCP 21

FTP (File Transfer Protocol) uses two primary TCP port numbers for its operation. The first port, TCP 21, is designated for control communication. This is where commands and responses are exchanged between the client and server during an FTP session. This connection is crucial for establishing and managing the session, including authentication and file-specific commands. The second port relevant to FTP is TCP 20, which is used for data transfer in active mode once the connection has been established. However, the control communication, which primarily manages the session and transfers commands, operates exclusively over TCP 21. Understanding the role of these ports is integral when configuring and troubleshooting FTP services.