There are different FTP applications based on different operating systems, and all of them follow the same protocol, so that the users can transfer their files to others or obtain files from other users’ environments.square steel tubing prices
Like most Internet services, FTP is also a client/server system. The user connects to the FTP server program on the remote host through a client program supporting FTP protocol. The users send commands to the server program through the client program. The server program executes the commands issued by the user and returns the results to the client. For example, a user sends a command that requests the server to send a copy of a file to the user. The server responds to this command and sends the specified file to the user’s machine.
In the use of FTP, the users often encounter two concepts: “Download” and “Upload”. “Download” file is to copy files from the remote host to their own computer; the “upload” file is to copy files from their own computer to the remote host.
When using FTP, you must login first, and upload or download files only after you get the corresponding permissions on the remote host. That is to say, if you want to transfer files with which computer, you must have the appropriate authorization of which computer.
This situation violates the openness of the Internet. There are more than ten million FTP hosts on the Internet. It is impossible to require every user to have an account number (or ID) on every host. Anonymous FTP is designed to solve this problem.