Firewall Passive

FTP allows you to choose a port or direction that a data connection uses.

Although it might seem practical for all data connections to originate from the client machine and end at port 20 on the server machine, you can choose to have the server assign an IP address and port number on the server side and have the client originate a connection to the server address. This is called passive data connection, where the client connects out to the server.

The active data connection is when the client requests that the server originate a data connection and terminate at an IP address and port number of the client's choosing, where the server connects out to the client.

Specify the passive data connection mode as: