Joey’s Notes: VSFTP FTP server on RHEL 5.x
By strongJoey Prestia/strong
p File Transfer Protocol (FTP) utilizes Transmission Connection Protocol (TCP) communication and listens on port 21 for incoming client connections by default. The connection to this port from the FTP client will form the control stream from which commands are passed from the FTP client to the FTP server and on occasion from the FTP server to the FTP client. FTP uses a separate connection for control and data. So for the actual file transfer to take place, a different connection is required which is called the data stream. Depending on the transfer mode, the process of setting up the data stream is different. Port 21 for control, port 20 for data. /p