Shulou(Shulou.com)06/02 Report--

In this issue, the editor will bring you about what the virtual host ftp name is. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

FTP in a virtual host is an acronym for File Transfer Protocol (File transfer Protocol), which is used to transfer files between two computers.

It is much more complicated than the HTTP,FTP protocol. Because the FTP protocol uses two TCP connections, one is the command link, which is used to pass commands between the FTP client and the server. The other is the data link, which is used to upload or download data.

FTP protocol has two working modes: PORT mode and PASV mode, which means active and passive in Chinese.

The PORT (active) connection process is that the client sends a connection request to the server's FTP port (default is 21), and the server accepts the connection and establishes a command link. When it is necessary to transmit data, the client uses the PORT command on the command link to tell the server, "I have opened the port, you come and connect me". So the server sends a connection request from port 20 to the port of the client, establishing a data link to transmit data.

The PASV (passive) connection process is that the client sends a connection request to the server's FTP port (the default is 21), and the server accepts the connection and establishes a command link. When data needs to be transmitted, the server uses the PASV command on the command link to tell the client, "I have opened the port, you come and connect to me." So the client sends a connection request to the port of the server and establishes a data link to transmit data.

The command link connection method of the two ways of FTP is the same, while the method of establishing data link is completely different.

The above is what the virtual host ftp name is shared by the editor. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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