What is the difference between the active and passive methods of FlashFXP

The active mode is that the client specifies the port and the server actively connects, which has high requirements for the server, and if the client is behind the firewall, the active connection from the outside to the inside is usually easy to block. If you are mapping an internal and external machine, you have to map both the control port and the data transmission port, but because the data port is randomly assigned by the client and is not fixed, this also makes it more difficult to establish a connection.

The passive mode relieves the pressure on the server to a certain extent, with the server specifying the port and waiting for the client to initiate the connection.

FTP active mode means that FTP will use its own port 20 to actively establish a connection with the client, and an error will occur when the client network does NAT. Think of the NAT port as if the client established a connection to the FTP port 20.

Active mode: The FTP client connects from any non-special port (N > 1023) to the command port of the FTP server, port 21. The client then listens on port N+1 (N+1 >= 1024) and sends commands to the FTP server over port N+1 (N+1 >= 1024).

The server will in turn connect to the user's locally specified data port, such as port 20.

Passive mode: In passive FTP, both command connections and data connections are sent by the client, which solves the problem that the inbound connection from the server to the client's data port is filtered out by the firewall. When an FTP connection is opened, the client opens two arbitrary non-privileged local ports (n >; 1024 and n+1).

The first port connects to port 21 of the server, but unlike active FTP, the client does not submit the port command and allows the server to connect to and from its data port, but instead submits the pasv command. The result of this is that the server opens an arbitrary unprivileged port (p >; 1024) and send the port p command to the client. The client then initiates a connection from the local port N+1 to the server's port P to transmit the data.

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Active FTP is good for the management of the FTP server, but bad for the management of the client. This is because the FTP server is trying to establish a connection to the client's high-level random port, which is likely to be blocked by the client's firewall.

Passive FTP is good for the management of the FTP client, but not for the management of the server side. This is because the client has to establish two connections to the server, one of which is connected to a random port in a high position, and this port is likely to be blocked by the firewall on the server side.

You're talking about active and passive skills.