Thursday, April 11, 2013

NetFlow on IOS

Some quick articles are here for me to remember more than they are anything else...

Configuring NetFlow on switches and routers is pretty straight forward.  There are a couple of things to keep in mind:

  • Support or features per device vary
  • Are you looking for layer 2 or 3 traffic?

Netflow was designed to report on traffic being routed.  Therefore you may not see traffic that stays on the same VLan without extra configuration.

To turn on NetFlow:
R1(config)#interface fa0/1
R1(config-if)#ip route-cache flow

Next export the info to a network management station of some sort:
R1(config)#ip flow-export 2055 version 5   (2055 is the UDP port (optional) and version can be 5 or 9, depending on what you NMS supports)

Enabling layer 2 for NetFlow on a Vlan:
R1(config)#ip flow export layer 2-switched vlan 10,20-25     (for VLan 10,20-25)

There are many more options available here:

Hopefully this helps you out.


No comments:

Post a Comment