Cisco netflow commands

Network management protocols like SNMP allow us to monitor our network.

Netflow configuration cisco 9300

We can check things like cpu load, memory usage, interface status and even the load of an interface. Other tools like NBAR allow us to see what kind of protocols are used.

One of the things we can’t do with those tools is tracking all flows in our network.

A flow is a stream of packets that share the same characteristics like source/destination port, source/destination address, protocol, type, service marking, etc.

NetFlow allows us to track these flows on our network. We can use this information to solve problems like bottlenecks, identify what applications are used, how much bandwidth they use etc.

For each of the flows, NetFlow will track the number of packets sent, bytes sent, packet sizes and more.

You can configure your router to keep track of all flows and then export them to a central server where we analyze our traffic.

In this lesson I will show you how to configure NetFlow on a Cisco IOS router and we will take a look at a NetFlow server.

Configuration

This is the topology we will use:

cisco show netflow version

cisco show netflow cache