What Is FTP?
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FTP - Technical Background

FTP is the acronym for File Transfer Protocol. FTP, one of the Internet protocol standards, is a simple and powerful way to exchange files between computers on the Internet. The FTP connection requires two parties: the Client and the Server. 3D-FTP is an FTP Client application that makes a connection to the FTP Server, which authenticates the connection request and shows a list of files that reside on the server. In addition to the FTP Client, users must be able to connect to the Internet (via a modem, cable modem, ADSL connection or local area network) to establish a connection. The Client's access rights determine what the Client can do on the server. For public FTP Servers, the Client is normally allowed to view a list of files and to download files. For private FTP Servers (like those used to maintain the web Server pages), the Client can list, download, upload and delete files and create and modify folders.

An FTP Client-Server session consists of two connections:

·Control connection: this stays open for the duration of the session. All FTP Commands are sent via control connection. Normally occurs to port 21 on the server.  
·Data connection: this opens and closes on each data download, upload and directory listing request.  

The FTP Server runs on the computer that is permanently connected to the Internet. It waits for the connection requests to port 21 from the FTP Client. When an FTP Client requests connection, the FTP Server authenticates the Client by requesting it to send the username and password. If these are valid, the Server allows the Client to send extra commands, such as request a file listing or download a file.

The FTP Server normally grants access only to a limited set of files and directories on the server, so the user might get the error message Permission Denied when trying to upload a file or change a directory. These permissions are granted and controlled by the FTP Server administrator.





Related Topics:

Making your first connection
Ordering Information
Evaluation vs. Full version