What would be the easiest way of getting packets dropped by the firewall in netflow?

We are using netflow to monitor our bandwidth but we would also like to log those dropped packet to see who is sending
us unwanted traffic.

Hi,
this is old post, however i have same question.....

is it possible to see if packets was filtered in firewall in netflow?
I assume that not as it is not purpose of netflow, right?