What is the linux ftp port number?

There are two linux ftp port numbers: "20" and "21"; port 20 is used to transmit data, and port 21 is used to transmit control information. Whether ftp uses 20 as the port for data transmission is related to the transmission mode used by FTP. If active mode is used, the data transmission port is 20; if passive mode is used, the final port to be used must be decided through negotiation between the server and the client.

#The operating environment of this tutorial: linux7.3 system, Dell G3 computer.

File Transfer Protocol (FTP) is a set of standard protocols for file transfer on the network.

FTP allows users to communicate with another host through file operations (such as adding, deleting, modifying, checking, transferring files, etc.). However, users do not actually log in to the computer they want to access and become a full user. They can use FTP programs to access remote resources, allowing users to transfer files back and forth, manage directories, access emails, etc., even though the computers on both sides may have different configurations. operating system and file storage method.

Port number of ftp in Linux

By default, the FTP protocol uses two TCP ports, 20 and 21, of which 20 is used to transmit data and 21 Used to transmit control information.

However, whether to use 20 as the port for data transmission is related to the transmission mode used by FTP. If active mode is used, the data transmission port is 20; if passive mode is used, the specific port used ultimately depends on the server side. Negotiate with the client to decide.

Extended information:

Like most Internet services, FTP is also a client/server system. Users connect to a server program running on a remote computer through a client program.

Provide services in accordance with the FTP protocol. The computer that transfers files is the FTP server, and the computer that connects to the FTP server and follows the FTP protocol to transfer files with the server is the FTP client.

To connect to the FTP server, users must use FTP client software. Usually Windows comes with the "ftp" command, which is a command line FTP client program.

Other commonly used FTP client programs include FileZilla, CuteFTP, Ws_FTP, Flashfxp, LeapFTP, etc.

1. Login to FTP server

• Anonymous user: FTP Password: FTP

• User: ANONYMOUS Password: any electronic Email

2. Display file information: DIR/LS

3. Download file: GET file name (download to the current directory)

4. Upload file: PUT file name

5, multiple file download: MGET

6, multiple file upload: MPUT

7, exit: BYE

8 , Help: HELP

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