# FTP

EN | ZH

### FTP¶

FTP (File Transfer Protocol) is one of the protocols in the TCP/IP protocol suite. The FTP protocol consists of two components, one for the FTP server and the other for the FTP client. The FTP server is used to store files. Users can use the FTP client to access resources located on the FTP server via the FTP protocol. When developing a website, the web page or program is usually transferred to the Web server using the FTP protocol. In addition, because the FTP transmission efficiency is very high, this protocol is generally used when transferring large files on the network.

By default, the FTP protocol uses the 20 and 21 ports of the TCP port, where 20 is used to transfer data and 21 is used to transmit control information. However, whether to use 20 as the port for transmitting data is related to the transmission mode used by FTP. If the active mode is adopted, the data transmission port is 20; if the passive mode is adopted, which port is ultimately used for the server side. Negotiate with the client to decide.