Which of the following services is used in FTP ?

Correct option is B

FTP (File Transfer Protocol) uses TCP (Transmission Control Protocol) for reliable data transfer between the client and server. TCP ensures that the files are transferred without errors and in the correct sequence by establishing a connection-oriented communication.

Important Key Points:

1. FTP uses two separate TCP ports:
• Port 21: For control commands.
• Port 20: For transferring data.
2. TCP provides reliable and ordered delivery of data, which is critical for file transfers.
3. FTP does not use UDP, as UDP is connectionless and does not guarantee reliable data delivery.

Knowledge Booster:

• UDP (User Datagram Protocol): A connectionless protocol used in applications where speed is prioritized over reliability, such as video streaming.
• SMTP (Simple Mail Transfer Protocol): Used for sending emails, not file transfer.
• DNS (Domain Name System): Resolves domain names into IP addresses, unrelated to FTP file transfer.
• Secure FTP (SFTP): A secure version of FTP that encrypts data using SSH, still relying on TCP.