Hi Brettow,
"port forwarding" can be a confusing concept initially but I'll give you a quick crash course because that's where your solution resides.
On your residential network (LAN), all the network devices have their own IP address.
For instance:
IPCam1: rtsp://192.168.1.100:554
IPCam2: rtsp://192.168.1.101:554
On the Internet side (WAN), your network shows only 1 public IP address (assigned by your ISP, permanent or changing periodically).
rtsp://Public_IP:554
So when you access your camera from outside your home, this is the public IP address that you use with the port 554, and the router can redirect the RTSP URL to the internal IP address of the first available camera.
(WAN) rtsp://Public_IP:554 ---> (LAN) rtsp://192.168.1.100:554
This is where the port forwarding is needed. Since there is only 1 public IP, we use instead different ports for each connection to target the desired camera.
It's done via a table in your router (they all have a "port forward" or "port trigger" section) where you specify that incoming external connections from
specific ports have to be sent to a
specific internal IP address.
rtsp://Public_IP:554 ---> rtsp://192.168.1.100:554
rtsp://Public_IP:555 ---> rtsp://192.168.1.101:554
rtsp://Public_IP:556 ---> rtsp://192.168.1.102:554
^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^
THIS EXTERNAL URL >>BECOMES>> THIS INTERNAL URL
So in the example above, the port on the public url can be almost anything you want, as long as that table in your router forwards it to a valid internal IP and port.
I hope it makes sense. I published this article on the subject some time ago with some pictures. The only difference is that it was explained with HTTP/80 instead of RTSP:
http://www.gadgetvictims.com/2010/05/how-to-access-your-ip-camera-from.html
Cheers!