I am not that good at network problems, so I apologize in advance if I am unable to explain the question well enough. I started working at the company which deals with IP cameras and security systems. They have this network installed and they're fine with it, but I'd like to help them make it better and I have two questions.
This is the general sketch of the network:
I made up the IP addresses and stuff. They have two connections to the Internet, cable and ADSL. Each router has its DHCP server turned on, and they give the IP addresses corresponding to the subnets 192.168.200.1-254 (cable) and 192.168.1.1-254 (ADSL).
On the cable router, we usually set-up port forwarding so we can access to the IP cam from the outside. We setup the DynDNS to point towards our dynamic IP address and we choose a port and forward it to the static private IP address of the IP camera.
They have the ADSL connection as well, because you can't access to the IP camera if you're on the same network with it, i.e. you need to access it from the outside, and I tried to illustrate this situation in the image below:
So, we need ADSL to be physically on a different network when we access our IP cameras, and then port forwarding works.
My first question is, why does it not work in the first case? When I am on the same network? The way I see it, I type the address myfirm.dyndns.com:445 in my browser, DynDNS translates it and I get the address 82.13.45.96:445 and I try to establish the connection with it aaaand... port forwarding doesn't happen? Why?
The second question is about NAS. I'd like to access NAS when I am on the ADSL connection as well. Right now I can't, since the NAS is in the 192.168.200 subdomain with its static IP address (there is an error in the picture showing the NAS belongs to the other domain, I made a mistake while drawing it). Is there a way to make this possible?