Port 80 is for the web interface and port 8081 is for MJPEG streaming. None of them is hardcoded - both can be changed through the UI.
Normally all you need is to forward to port 80. However, if you want to access the MJPEG stream directly (i.e. without a surrounding frame or the UI), you'll need to forward to port 8081.
I don't understand why port 80 isn't a choice for you, but if it really isn't, you can change it to whatever port you want, in Expert Settings.
I feel the need to mention that the forwarded (external) port can be different from that to which you forward (internal) - your router's UI should allow you to choose, say, port 12345 and forward it to your motionEye's unit IP address, on port 80.
caveflyer wrote:I'm 100% sure I've got the port forwarding set up correctly... I verified it by port forwarding another commercial web cam, and it worked.
Using port 80 is not possible in my situation, but, is port 8081 hard coded somewhere? I've been using the part of the admin interface that lets you pick a port, and I've tried 88 and 98, but neither works? What's the deal with 8081?