The ActionDispatch::RemoteIp middleware can provide the remote IP correctly as a property of the request object. It has an option to provide a list of trusted reverse proxies which needs to be exposed to the user. The installer should also expose this. It only needs to be in settings.yaml since middleware can't dynamically reload config.

This will replace the existing IpFromRequestEnv concern so it can be used application wide.

https://api.rubyonrails.org/classes/ActionDispatch/RemoteIp.html