While not entirely what you’re looking for, Glen, I have the KeepConnect device at both of my locations. What you might find interesting is the description on their website about how it works: the rationale behind a full HTTPS request with 200 (success) return vs. other methods commonly used like a ‘Ping’ request. They have advanced features that handle each of those, plus being able to navigate around a DNS failure, as well. It’s interesting reading…