I want to give to my ISP ability to measure connection speed to my router. ISP will run "client-side" iperf3. Roter will run "server-side" iperf3.
I don't care about security reasons in this case.
I don't care about router's memory degradation too. I run OpenWRT from sd-card.
So I just want to know how to setup iperf3 server. Autorun it after booting. Make it accessible from WAN. Save the logs, if someone run iperf test.