The FTP protocol specifies different well-known port numbers for control connections and data connections, the well-known port number for control connections is 21, and the well-known port number for data connections is 20. According to the provisions of the TCP protocol, FTP servers use well-known port numbers 20 and 21 to provide services, and FTP clients use temporary port numbers to send requests. The FTP server receives and responds to the FTP client's request and provides the FTP client with the required file transfer service. The FTP client sends a service request to the FTP server in the computer network. Port 21 is a command port used to transmit control flow and accept related FTP commands and parameters issued by the client. By default, two ports 20 and 21 are used, a data port and a command port, and port 20 is a data port for file transfer between the client and the server data flow. How Does FTP Server Work?įTP is based on the TCP protocol service, which is a file transfer protocol on the Internet. This process is carried out by the FTP server. The user receives the file and places it in the user's working directory. The server responds and sends the file to the client. Simply put, the user sends a command to the server, asking the server to send a file to the user.

The user issues a command on the client, and the remote host server executes the command issued by the user after receiving the command, and returns the execution result to the client. Users use a client that supports the FTP protocol to connect to a server program on a remote host. FTP is a protocol specifically used to transfer files.įTP is a client/server system. FTP, the file transfer protocol is a set of standard protocols for file transfer on the network, using the client/server model. They provide services in accordance with the FTP protocol. File Transfer Protocol Server is a computer that provides file storage and access services on the Internet.

What is a ftp server 3ds