Netflow is normally enabled on a per-interface basis for limiting the amount of exported flow records and the load on the router components.
By default, it will capture all packets received by an ingress interface and IP filters can be used to decide if a packet can be captured by NetFlow.
Once accurately configured, it can even allow the observation and recording of IP packets on the egress interface.
Custom settings can also be done on the Netflow implementation according to the requirements in a variety of practical scenarios.
NetFlow data from dedicated probes can be efficiently utilized for the observation of critical links, whereas the data from routers can provide a network-wide view of the traffic that which will be of great use for capacity planning,
accounting, performance monitoring, and security