I have 6 webcams, a X10 webserver, and two other SBCs connected to my local home router. Using a DDNS service (lets call the domain “myhome.com” for this example), “mydomain.com” points to the IP that my ISP has assigned to my home WAN connection. This DDNS service will always keep my domain name pointing to the currently assign IP of my WAN.
For the purpose of accessing the Spark, I set the webserver app to port 9700 and used the URL mydomain.com:9700.
All that is needed to gain access from the Internet (anywhere) is to configure my home router to forward port accesses (hence, the term port forwarding) to the device (webcam or other “thing”) that is configured to respond to a particular port.
Since this setup has been working, providing global access to my webcams and other devices for many years now, I was expecting this to work with the Spark Core.
What is difficult for me to understand is why the domain name resolves to my ISP assigned WAN IP with WIFI on but not when it is off (off on the Smartphone that is, WIFI on home network is still running).
This forces the phone to use the 4G network to find my WAN IP. In either case, it needs to find a DNS outside my local WIFI network to resolve the domain name.
It would seem that if the port forwarding will not work from an Internet access point outside my home network, then it should also not work inside the local network using the same domain name in both cases.
Just wondering if this is a Spark Core constraint. It also does not make sense to me. Does anyone understand how this could happen?