This is a challenge I can´t resist .
I will probably ask stupid questions, misunderstand and ask for more information so please beware ;). So here it goes.
This has nothing to do with Netcam Studio (NCS) per se, but it has everything to do with how the computer is accessed running NCS. I need to structure this into 3 cases and also trying to visualize in this text based forum.
Case 1: NCS_app/iPhone to NCS at parents house. This is working.
NCS_app/iPhone --> DDNS_parents/WAN_public_IP --> parents_house --> router/port_forwarding/LAN_IP:8100 --> computer/NCS:8100
Case 2: using VPN to your house and continue to the computer at your parents house running NCS. This is not working.
NCS_app/iPhone/VPN --> DDNS_home/WAN_public_IP --> your_home --> router/VPN_server --> change LAN to your parents house --> computer/NCS:8100.
-I assume that you can access the devices on your home LAN from the iPhone so you know that the VPN works?
-is the VPN server in the router or is the VPN server on a computer on the LAN so the VPN traffic tunnels through the router first?
-a correct configured VPN server (in router or local computer) do not allow you to continue to another LAN. For example, if your set up the VPN in the iPhone to connect to the LAN with IP 192.168.2.x then the VPN server block you from connecting to for example 192.168.4.x. This is purely for security… If you want to connect to the LAN with 192.168.4.x you must set up a new VPN connection to that LAN.
-stupid question, but why don´t you do it like in case 1?
Case 3. connecting the home computer to parents computer. Use the NCS web client on the laptop.
You don´t say anything how you do it today so it is difficult for me to say what is the problem. However, you can do this connection in two ways:
1.setting up a VPN between the two locations,
2.using port forwarding in the router at your parents house.
If you want to have access to everything on the parents LAN then use (1) with VPN. If you need access only to NCS it is easier to use port forwarding in the router at your parents house as (2).
Just a reminder; you need everything to be on Static IP on the LANs and of cause DDNS_home and DDNS_parents on the public IP side.
That´s all for the moment ;).