I have two printers. Each of the printers are connected to it's own Pi with Octoprint. Connected to each pi is also a webcam. Both PI's have designed static IP addresses. (172.16.0.150 and 172.16.0.160).
I'm using Octolapse and MJPG-streamer. Within my LAN I can reach the cams by IP address:8080 they both work.
My router can't have to devices connected to the same port (8080). It doesn't allow to have two instances with the same port.
So I want to set the second stream to for example port 8081. But I can't get it to work.
I'm guessing that I have to specify somewhere (else than inside Octoprint/Octolapse) that I want it to stream - not on the standard 8080, but to another port.
This sounds like you are planning on exposing your OctoPrint instances on the public internet. Note that this is strongly discouraged and there are much safer ways to achieve connectivity from outside of your LAN.