Hello Dear Fulvio.
Ipt-netflow is very fast and effective Netflow exporting module for Linux kernel. Designed for Linux router with heavy network load. This is netfilter/iptables module adding support for NETFLOW target. It’s not using conntrack for performance reasons.
Ntop cam receive and analyze netflow data
http://sourceforge.net/projects/ipt-netflow/
Can you include this module in the next version
Thank You