Create hostname.pflow0:
flowsrc 192.168.103.1 flowdst 192.168.103.9:3001
flowsrc = your sensor
flowdst = your collector
$ ifconfig pflow pflow0: flags=41<UP,RUNNING> mtu 1492 priority: 0 pflow: sender: 192.168.103.1 receiver: 192.168.103.9:12345 groups: pflow
+ make sure you pass the traffic from sensor to collector