This blog may need prior reading of my first blog about Flexible NetFlow. We have already discussed about the advantages of Flexible NetFlow and migration from traditional NetFlow versions to FNF. To make this transition smooth Cisco provides the option of pre-defined flow records which can be used to configure Flexible NetFlow without investing a lot of time. And as I mentioned earlier it also helps your existing NetFlow V9 collector to parse exported data. However to use Flexible NetFlow to its fullest potential or to monitor a specific network behavior, you should create your own customized records.
Let’s see how to configure Flexible NetFlow to export flow statistics. Flexible NetFlow export can be configured in three easy steps.
1. Configure the exporter
2. Configure the Flow Monitor with the pre-defined Flow Record and Flow Exporter attached to the monitor.
3. Add the Flow Monitor to the interface to monitor either ingress (input) or egress (output traffic).
1. Configuring Exporter
Flow exporter can be configured with a unique name. Multiple Flow exporter profiles can be configured. Below is the configuration to configure Flow Exporter.
flow exporter <exporter name>
destination <ip address of ME NFA>
transport udp <port number>
Example configuration:
flow exporter me_nfa_analyzer
destination 192.168.1.1
transport udp 9996
2. Flow Monitor and Flow record configuration
Flow record configuration defines the fields exported via NetFlow protocol. Flexible pre-defined flow records are based on the original NetFlow ingress or egress caches. Cisco provides a unique keyword to identify the pre-defined records and these records can associated with a Flexible NetFlow Flow record configuration. The Flexible NetFlow “netflow-original” and netflow ipv4 original-input are predefined records and these two records can be used interchangeably to export the basic key fields and time stamp fields. Flow monitors can also include packet sampling information if sampling is required.
flow monitor <monitor name>
record netflow-original
exporter <exporter name>
cache timeout active <seconds>
cache timeout inactive <seconds>
Example Configuration:
flow monitor me_nfa_monitor
record netflow-original
exporter me_nfa_analyzer
cache timeout active 60
3. Adding Flow Monitor to the interface
Flow Monitor has to be attached to a specific physical or logical interface to export flow statistics for that particular interface. Below is the configuration to attach flow monitor to a specific interface.
interface <interface name>
ip flow monitor <monitor_name> input
Example Configuration:
interface serial0/0
ip flow monitor me_nfa_monitor input
And the above configuration can be verified by “show flow monitor” command. As I mentioned earlier Flexible NetFlow has numerous advantages and has the power of supporting new performance monitoring statistics as soon as they are available. Flexible NetFlow is an evolving technology available in Cisco devices to help with visibility into how network assets are being used and the network behavior.
Please find more information on FNF here.
ManageEngine constantly studies the market and user demands to support new technologies. In fact ManageEngine NetFlow Analyzer is the first tool to support multiple bandwidth and performance monitoring technologies like NetFlow, NBAR and CBQoS in the market. And currently ManageEngine NetFlow Analyzer supports Flexible NetFlow without any issues. Please write your questions to netflowanalyzer-support@manageengine.com. We are happy to assist you at any moment.
Thanks
Raj
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