modprobe ip_nat_ftp - if passive works but active writes error after PORT command or hangs. modprobe ip_conntrack_ftp - if forwarding rule filtering based on state. remember to accept RELATED tcp connections. see modinfo ip_conntrack_ftp ... parm: ports int array (min = 1, max = 8) if you want to access ftp servers unusual ports. then you would have to add some entry to /etc/modules.conf with options line or in script you use add ports parameter.
