Aaron J. Prisk

On OBS, you can add another RTSP stream as a Media Source by clicking the + under SOURCES > Media Source > Create New > Uncheck Local File > Under Input, paste the full RSTP stream of your ipcam.

I do something similar to do split screen game streaming where my friend and I's streams are shown side by side.

I didn't include it in my tutorial, but here's a good write-up for setting one up on Ubuntu:
https://www.digitalocean.com/community/tutorials/how-to-set-up-a-firewa…

And here's a pretty good write-up for using the PF firewall on FreeBSD:
https://www.cyberciti.biz/faq/how-to-set-up-a-firewall-with-pf-on-freeb…