I just know that Netflow can tell us about the traffic of the network, but really I don't know how it works on FreeBSD. I understand that I should install different ports but after that what I should do?
- netflow export from your network device(s) - e.g. on Cisco IOS "ip flow-export destination x.x.x.x yyyy"
- a netflow collector daemon/application to stick the exported flow info into a database
- an analysis tool to report on the netflow information collected.