FTP means File Transfer Protocol. This protocol is for exchanging files over the Internet. FTP works in the same way as HTTP for transferring Web pages from a server to a user’s browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet’s TCP/IP protocols to enable data transfer.
FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).
There are two computers involved in an FTP transfer: a server and a client. The FTP server, running FTP server software, listens on the network for connection requests from other computers. The client computer, running FTP client software, initiates a connection to the server.
Once connected, the client can do a number of file manipulation operations such as uploading files to the server, download files from the server, rename or delete files on the server and so on. Any software company or individual programmer is able to create FTP server or client software because the protocol is an open standard. Virtually every computer platform supports the FTP protocol.
This allows any computer connected to a TCP/IP based network to manipulate files on another computer on that network regardless of which operating systems are involved (if the computers permit FTP access).
FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. However, any FTP client program with a graphical user interface usually must be downloaded from the company that makes it.
Read Here: How To : Installing an FTP Server on Linux