Use the FWFRIENDLY statement to specify how data connections are to be set up between the client and the server.
.-FWFRIENDLY FALSE------. >>-+-----------------------+----------------------------------->< '-FWFRIENDLY--+-TRUE--+-' '-FALSE-'
FWFRIENDLY TRUE ; FTP client is firewall-friendly
When the connection to the server is IPv6, data connections are set up from client to the server regardless of the FWFRIENDLY setting.