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Netflow

Version 5: limited to IPv4 flows
Version 9: template-based, IPv4, IPv6, MPLS, BGP.
Netflow Flow Export Format
Cisco Flexible NetFlow

Netflow 5 Configuration

ip flow-export version 5 ip flow-export destination 10.10.10.100 2055 ip flow-export source Loopback0 ip flow-cache timeout active 10 ip flow-cache timeout inactive 25 ip flow-top-talkers top 10 interface vlan 100 ip flow ingress ip flow egress show ip cache flow show ip flow top-talkers show ip flow export

Flexible Netflow Configuration

Flow Records - the definitions of what you want to capture

flow record MYRECORD match ipv4 destination address match ipv4 tos collect interface output collect counter bytes collect counter packets

Flow Exporter - tool to send the traffic to a remote system

flow exporter MYEXPORTER destination 10.10.10.100 source Loopback0 transport udp 2055 export-protocol netflow-v9

Flow Monitor - applied to the interface to actually monitor traffic

flow monitor MYMOITOR record MYRECORD exporter MYEXPORTER interface vlan 100 ip flow monitor MYMONITOR input ip flow-export version 9

Flow Sampler - used to limit the load on the router gathering data