Howard Nurse, W6HN
Welcome to the group, nice to have you here. You and I have talked much about CommCat in the past.
The answer to your question has several parts, but, yes, you need to know the IP of your home station when accessing from a remote location.
The first important IP is your home Internet IP. You can use a dyn service to solve that. (My IP here at home...Comcast...hasn’t changed in many years, but I still keep use a service.)
The IP of the RigPi box on your LAN also has to remain constant because you need to open a port on your router to that IP. (Mine stays pretty constant despite rebooting frequently.) There are articles on the Internet showing how to make the raspberry pi stick to a static IP, with a link for one article in Help.
The final answer has to do with connecting while at home. The RSS uses a domain name “rigpi.local” which can be used to connect when you are on your home network. It uses a service called Bonjour to broadcast the name and IP to other computers on the same network. (Android devices do not support Bonjour, so you have to use the IP.)
1. Internet IP for your home must be known.
2. LAN IP for the RSS must be constant so the router can access it.
3. At home you may be able to I use rigpi.local depending on the computer you are using.