Fluke Computer Accessories manual Appendix 1 Device Configuration, Ip cef

User’s Guide – version 3.5 NetFlow Tracker

Appendix 1: Device Configuration

This is a brief guide to setting up NetFlow on various types of device. Note that if your device isn’t listed here it does not mean it is not supported by NetFlow Tracker; please ask your device vendor for a guide to enabling NetFlow.

Enabling NetFlow Export/NDE on a Cisco Router or Layer 3 Switch

For more information on this subject, visit http://www.cisco.com/go/netflow. We recommend that only people with experience in configuring Cisco devices follow these steps. If in doubt, contact your network administrator or Cisco consultant. Note that if you are running hybrid mode on a layer 3 switch you must configure IOS on the MSFC and CatOS on the Supervisor Engine. Native IOS also requires extra commands; these are documented below.

Enabling Netflow Export on an IOS Device

In configure mode on the router or MSFC, issue the following to enable NetFlow Export:

ip cef

This enables Cisco Express Forwarding, which is required for NetFlow in most recent IOS releases.

ip flow-export destination <address> 2055

Use the address of your NetFlow Tracker machine and one of the ports configured in the Listener Ports settings page. Port 2055 is monitored by default.

ip flow-export source loopback 0

The source interface is used to set the source IP address of the NetFlow exports sent by the router. NetFlow Tracker will make SNMP requests of the router on this address. If you experience problems you can set the source interface to an Ethernet or WAN interface instead of the loopback.

ip flow-export version 5 [peer-as origin-as]

or

ip flow-export version 9 [peer-as origin-as]

This sets the export version. Version 5 and Version 9 both support all of the features NetFlow Tracker is capable of using; if you have a Native IOS switch you may need to use version 9 to work around a bug – this is described below. If your router uses BGP, you can specify that either the origin or peer ASes are included in exports – it is not possible to include both.

Note that enabling or disabling NetFlow version 5 or version 9 (not version 1) on a 12000 series router causes packet forwarding to stop for a few seconds while the route processor and line card CEF tables are reloaded. To avoid interruption of service to a live network, apply this command during a change window, or include it in the startup-config file to be executed during a router reboot.

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