Is it possible to get NetFlow to transmit it's data from a loopback interface? Right now it transmits from the interface that leaves the box, whatever that may be. I need it to transmit from a loopback interface so if routing ever changes the flow source does not change.

Is it possible to get NetFlow to transmit it's data from a loopback interface? Right now it transmits from the interface that leaves the box, whatever that may be. I need it to transmit from a loopback interface so if routing ever changes the flow source does not change.

I am going to answer my own question in case this may benefit someone down the road.

To do this you have to mark the packets that are of interest. In my case, it's NETFLOW on UDP port 2055 outbound. Once you have marked the packets then you do a src-nat rule in the firewall that does a net-map using the source IP of the loopback interface.

Once you set that up you'll need to restart netflow so the connections are natted properly.

This worked for me and I hope it helps you.

-J