If I wanted to get code-nerdy, I could bypass the whole OpenHAB/Domoticz stuff and go straight to coding. But ouch, there's enough coding involved in the others to make it challenging, and I'd be lacking a friendly digital user interface.
Good comparison of common VPN tools and their weaknesses
no 5 MHz, but everything else and a good price
don't let it through the firewall/NAT, obviously
A clever design, which might not be hard to mimic! Basically, the frame becomes the heatsink as well as supporting everything. Using the hollow space in the posts might even be good for cable management.
Cheaper than BTGuard and TorGuard.
24v Passive PoE is scarce, but also available by Tycon Power and Netonix. MikroTik is even cheaper, and available as a managed router!