Configuring NetFlow
Example 7-20 shows you how to enable NetFlow Switching for IP on a Cisco Router.
Example 7-20. Configuring NetFlow on a Router
Router(config)# interface
Router(config-if)# ip flow ingress
Router(config-if)# ip flow egress
The ip flow ingress command is used to capture traffic being received by the interface, whereas the ip flow
egress command is used to capture traffic being transmitted by the interface.
Note
For Cisco IOS prior to releases 12.2(14)S, 12.0(22)S, or 12.2(15)T, the ip route-cache flow command
was used to enable NetFlow on an interface.
For Cisco IOS release 12.2(14)S, 12.0(22)S, 12.2(15)T, or later, the ip flow ingress command is used
to enable NetFlow on an interface.
If CEF is not configured, NetFlow enhances the existing switching path (optimum switching).
If CEF is configured, NetFlow becomes a flow information gatherer and feature acceleration tool.
The router maintains current NetFlow cache to track all the flows passing through the device. The show ip
cache flow command or the show ip flow interface command can be used to view a snapshot of the current
flows stored in the router cache.
Example 7-21 shows a sample snapshot using the show ip cache flow command taken from the NetFlow
cache.
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