File Transfer Protocol (FTP) is used for file transfer between for computers on a local area network and the Internet. This technology is one of the most popular and allows both to download, and to unload necessary data on remote servers.
Instruction
1. For use of the protocol the user needs to install the special client program which will carry out connection to the remote computer. For connection implementation the user needs to specify these servers with which connection is executed. If data were specified successfully, in a window of the program the directories open for viewing are displayed by the server.
2. By means of elements of the interface of the used application you can how to move the folders which are available on the server to yourself on the computer, and to execute unloading of data on this server of your file system. The operations with files which are carried out by means of FTP clients practically do not differ from similar during the work with the system of the computer. For example, you can copy, cut and delete different folders and the selected documents.
3. In attempt of connection with a remote server through the program the certain network port on which the necessary request for performing connection and implementation of file sharing is transferred opens. Usually for implementation of connection port 21 and the separate ftp:// protocol which is specified at setup of the client is used. Also the program announces to the server need of use of a certain active or passive type of connection on which the server response and connection establishing for performing information exchange depends.
4. At active connection the server automatically opens for the user a certain port through which data exchange is made. All information from the server is transferred on the created connection. In an active mode of data exchange port 20 is usually selected, however the remote machine can select arbitrary value which does not exceed 1024. In the passive mode the server selects any port which numerical value exceeds 10000. After that the machine associates connection with the current session and directs necessary instructions and values to the computer of the client who begins to use the port selected with the server for connection and information transfer.
5. It should be noted that most of modern FTP clients prefer to establish passive connection in attempt of data transmission from the server. As soon as connection is created, file sharing implementation is possible. Thus the client computer defines connection type, and the server reports whether he is capable to execute data transmission on the specified conditions.