NetFlow data is network traffic statistic information. It is generated by network devices (i.e. routers, switches, firewalls, network probes etc.).
NetFlows contain only statistical information (source address, destination address, protocol, etc.), not the traffic itself. Therefore, it is free of confidential information.
For more information about NetFlow, visit http://www.cisco.com/go/netflow.
Currently, NetHound supports NetFlow Version 5 and Version 9 (with default template).