Specifies if passive or active data transfer mode should be used for uploads and downloads.
If the property is set to True, the passive mode will be used.
In passive mode, if the data connection is needed, the server opens listening socket
and accepts data connection to it. If active mode is used, the listening socket is opened by the client side.
Using passive mode is reasonable if a client is located behind a firewall or proxy software.
Default value is False.