FTP port & PASV

Usepassive-specifies whether the active or passive mode is used. Earlier, all clients used active mode and work well. Now, due to the existence of the Client Firewall, some ports will be closed,
In this way, the active mode will fail. In this case, the passive mode is required, but some ports may also be blocked by the server's firewall. However, because the FTP server needs its FTP service to connect to a certain number of clients,
Therefore, they always support the passive mode. This is why we need to use the original intent of the passive mode. To ensure that data can be transmitted correctly, the passive mode is obviously better than the active mode.
(Note: In active (port) mode, a data transmission channel is initiated by the server. The server uses Port 20 to connect to a port greater than 1024 of the client. In passive (PASV) mode,
The establishment of the data transmission channel is initiated by the FTP client, which uses a port greater than 1024 to connect to a port greater than 1024 of the server)

Why is port safer than PASV?

During FTP transmission, a dedicated connection is required to transmit data. There are two methods to establish a connection: the FTP Server opens a port, and the client can connect to the port to establish a connection. This is the PASV method. One is that the FTP client opens a port, and the server connects to the port to establish a connection. This is the port mode. Obviously, if the server opens a port, it means a port is opened to the Internet. Therefore, port mode is safer than PASV mode.

Summary: PASV is passive. FTP is passive, waiting for the customer to connect. Is it lazy! Poor security
Port is active, FTP actively connects with customers, so it is diligent and highly secure.

Some FTP accounts and passwords are correct but cannot be logged on,

The problem is that the FTP login requires the port connection method. the default PASV mode is usually used for FTP software connection. This FTP requires the port mode, so an error occurs when you enter the list. The solution is to change the port connection mode.

Many FTP accounts and passwords are published correctly, and you may not be able to connect to them.