File Sharing Through FTP
The File Transfer Protocol (FTP) is probably the oldest form of file sharing available to computer users, and it is also one of the most rudimentary—though it is still used widely for tasks such as downloading large binary files (usually software archives).
A user connects to an FTP server using a specialized program, usually simply called ftp on most systems, although many more full-featured graphical FTP clients are available (including Web browsers, which incorporate some FTP functionality). FTP is also built in to the standard windowing filesystem of Windows and Mac OS X.
When the FTP program connects to the server, it prompts for a username and a password; if what the user enters is correct for a user that exists ...