We're running a network with non-NetFlow-supported switches (3750s) and we're trying to use an external PC to and a SPAN session to collect traffic and forward it as NetFlow data to NTA. Initially, NTA showed an alert that it had received a NetFlow data stream from our PC, but it said we had to add it as a managed node. We added it, but set it to manage via ICMP only, because the PC is not set up for SNMP. Then I got a message saying "You have not enabled NetFlow data export on (the PC)", and it had a link to a Thwack article on how to enable NetFlow on Cisco switches. Now I'm not sure if I'm getting NetFlow data or not, but I suspect not because I haven't been able to search on Protocols or end points, etc.
I did find some documentation on Thwack that advised the following:
I added our server, but via ICMP only, so there was no option to include any interfaces. Do you think this would be a problem?
Yes - You'll have to add SNMP monitoring for the server and then add the interfaces.