Cisco Certified Network Associate (CCNA) Practice Exam

Which command is needed to enable NetFlow on an interface?

1. ip flow-export destination ip-address udp-port

2. ip flow ingress

3. show ip flow export

4. ip flow-export version version

The correct answer is: ip flow ingress

To enable NetFlow on an interface, the correct command is to use the option that specifies the flow direction on the interface. The command ‘ip flow ingress’ is used to enable the collection of inbound traffic flow statistics on that specific interface. By applying this command, the router begins to monitor and collect data about the packets entering the interface, storing key information about the flows, such as source and destination IP addresses, protocols, and port numbers. This configuration forms part of setting up NetFlow for traffic analysis and performance monitoring, allowing network administrators to gather valuable insights into traffic patterns and behaviors. Other commands listed serve different purposes. The command for exporting flow data to a destination would be used in conjunction with NetFlow but does not outright enable NetFlow on the interface itself. Similarly, commands for displaying flow information or specifying export version do not activate flow monitoring directly on an interface. Thus, ‘ip flow ingress’ is the appropriate command for enabling NetFlow traffic collection on an interface.