The Way FTP Works
Looking at how does FTP work, you start with the fact that FTP is an unsecured protocol. That alone will tell you that it is an older protocol, because in today’s Internet operations, security is a big concern. This means that when you transfer files, they are not encrypted and even names and passwords fly over the Internet where anyone can read them.
The actual file transfer takes place using FTP instead of HTTP in the URL address. For instance, to connect to an ftp server, you would type, FTP://188.8.131.52. FTP transfers, however, will be faster than other type of transfers because of the smaller overhead; these include HTTP or e-mail attachments. Today, users work with FTP to transfer large files.
To transfer data over the network, there are two transfer modes available; they are ASCII and Binary mode. When you use ASCII mode, you must avoid data corruption, and to do this all data must be in plain text format. When you use Binary mode, the sending machine sends a byte stream for each file, one byte for byte, and the recipient stores the byte stream as it receives it.
The FTP connection involves 2 ports, 20 and 21. Port 20 is the control connection, which is used to open and keep open a connection between the client (which wants the data) and the server (which has the data). Port 21 is the data connection, which receives the data file from the server. Logons can take place using anonymous FTP. This means that when logging on to a server, the account is Anonymous, and one doesn’t need a username or password.