NetFlow with Ntop

I had heard that Ntop supports Netflow on Linux.

I found a link / blog where someone else has played with this package for same or similar purposes. Let me share that here:
https://devops.profitbricks.com/tutorials/install-ntopng-network-traffic-monitoring-tool-on-centos-7/

I downloaded the Ntop package, and immediately it barked about the fact that I did not have kernel headers on the system.

This is bad, in my mind.

What box, running out in the field, would have kernel headers installed on it? That would be a bad security practice because it would mean that the box has a lot of stuff on it that it probably shouldn't have...specifically this would mean compilers, et al?

I also noticed that the package runs with a license code. There is a limited license it can run as, which is default configured.  But I'm not sure I like having software, at least for this purpose, that is dependent on licensing. I did not study whether it is a key license that is time expired, or if it calls out to a remote server to authenticate the license, et al.

I kind of stopped there. I did not play with it any further. I may come back to it, and if I do I will update this accordingly.