Which application layer protocol is commonly used for file transfer over TCP?

Which application layer protocol is commonly used for file transfer over TCP?

• A. DNS
• B. DHCP
• C. FTP
• D. HTTP

Answer: (C)

FTP is designed specifically for transferring files over a TCP connection. It uses two separate channels: a control channel for sending commands and a separate data channel for the actual file data. This structure supports reliable, orderly file uploads and downloads and is built into the protocol with commands for listing, retrieving, and storing files. Typically, the control channel runs on port 21, while the data channel uses port 20 in active mode or a dynamic port in passive mode, which also helps with firewall traversal. Other options aren’t devoted to file transfer: DNS and DHCP handle naming and network configuration, mainly over UDP, and HTTP, while it does transfer files, is built for web resource access with a request/response model rather than dedicated file-transfer operations. So FTP is the most appropriate choice for file transfer over TCP.

FTP is designed specifically for transferring files over a TCP connection. It uses two separate channels: a control channel for sending commands and a separate data channel for the actual file data. This structure supports reliable, orderly file uploads and downloads and is built into the protocol with commands for listing, retrieving, and storing files. Typically, the control channel runs on port 21, while the data channel uses port 20 in active mode or a dynamic port in passive mode, which also helps with firewall traversal. Other options aren’t devoted to file transfer: DNS and DHCP handle naming and network configuration, mainly over UDP, and HTTP, while it does transfer files, is built for web resource access with a request/response model rather than dedicated file-transfer operations. So FTP is the most appropriate choice for file transfer over TCP.