I wonder who doesn’t have such a miracle of technology as a laptop, PC or, at worst, an old computer? Probably, we no longer imagine our life without keys, social networks, browsing or developing various websites and programs, and, of course, the Internet. And you are aware of the principle of operation of the Internet, and in general, how and to whom it is transmitted. So today let’s talk about FTP.
One of the Internet standards is FTP (file transfer protocol), from the TCP IP family. FTP is a file transfer protocol, while copying one file from one system to another. It began its history of existence in the late sixties, but it is still used today. With it, you can also view files on FTP sites. To viewand copy files, you need to have a program for working with FTP sites, a simple browser is most often used, or else you can enter the “FTP”command in the OS command line.
When you have access to the Internet, you can download or upload files from to the World Wide Web sites. To use the FTP protocol, an FTP client is required, which provides access to the FTP server. Next you need to go through a simple authorization in the system, and you can connectanonymously (on large servers). In his work, he uses the so-called TCP transport protocol.
FTP is not that simple. When the client connects to the server, two-way communication takes place, which is supported by the protocol. One connection is remote access (via telnet); the second is direct data exchange. For its part, the FTP server opens port 21 (or passive open), and the FTP client active open. Until the FTP procedure is completed, the channel is in the active state.
You can work with file transfer using FTP in several modes: transfer of text files is ASCII mode, not text files (take for example pictures) is binary mode. You can switch between modes using the ascii and binary commands. The advantage of FTP, for example, over HTTP is that it allows you to transfer files faster, as well as when the connection is broken, to continue downloading from the place where everything was interrupted. It is used now, and can be useful in poor and unstable communications.