Networking :: Use FTP Client (for Example Ncftp) To Connect In Active Mode?

I want to use FTP client (for example ncftp) to connect in active mode. I have firewall (iptables) on my laptop and most of time I am behind rooter. With outgoing packets and with passive mode all is working fine.But some sites accept only active mode.I could open some port range in firewall and in rooter for active data packets, but I don't know how to solve security issues.So how should I correctly manage active ftp connection?

How can I set data port range when opening active connection with ncftp (or maybe another ftp client)?How can I limit that incoming connections to that ports range is accepted only by ncftp or else dropped?