FTP

File Transfer Protocol (FTP) is a network protocol, which was specified in a RFC in 1985. FTP is used for the transmission of a file in a TCP/IP network. Via FTP files can be transferred from a server to a client (download) or from a client to a server (upload). Therefore FTP uses separate TCP connections for commands and data transmission.
In order to use FTP, you need a FTP-client like Filezilla, LeechFTP or FTP Voyager, but today most browsers already have a built-in FTP-client.

At first a TCP-connection from client to server (standard port: 21) is established and commands (specified in an RFC) are transmitted. The server replies these commands with a status code.
Many FTP-servers, especially FTP-servers at universities, offer the so-called “anonymous FTP”. To use anonymous FTP, it’s not necessary to own a valid user account for the server, because everybody can login with the username “anonymous” or sometimes “ftp”. A password for logging in on the public account is not required either. Sometimes though, any password can be chosen, but then it is considered good form to use the e-mail address.