In order to reach an FTP server, a connection through an FTP client first needs to be established. This FTP client creates a TCP connection to the control port of the server (normally port 21) and is then able to send commands that the server subsequently answers. Following this, the data is transferred through another port. At this point, it’s important to differentiate between two different types of transfer modes. In active mode, the client, which uses port 1023, signals its IP address through port 21 during connection buildup. This process informs the server which port the client can be reached on. In passive mode, the server does not receive an IP address from the client (due to a firewall, for example) and offers the client a port through which a connection can be established.
Those using web-hosting solutions with FTP accounts profit from the quick and easy data transmission between the device and the web server. FTP software further assists these solutions by providing a sleek user interface that browser-based clients lack. FTP programs let the user sort and manage files into the existing directory structure with speed and ease. Administrators control the access rights of users who are able to simultaneously access the FTP server.