Question: Which connection is opened and closed during a session in FTP?

Answer:

Data Connection: The data connection is opened and closed as needed during the FTP session to transfer file data. The data connection is established separately from the control connection, and it serves the purpose of transmitting actual file content. The data connection can be set up in two modes: active mode or passive mode.

• • Active Mode: In active mode, the FTP client initiates the data connection by specifying an IP address and port for the server to connect to. The client listens on a specific port for the incoming data connection from the server. Once the data transfer is complete, the data connection is closed.
  • Passive Mode: In passive mode, the FTP server provides an IP address and port for the client to establish the data connection. The server listens on a specific port range for the incoming data connection from the client. Once the data transfer is complete, the data connection is closed.

To summarize, the control connection is opened at the beginning of the FTP session and remains open until the session ends. The data connection, on the other hand, is opened and closed as required during the session for transferring file data.