Sure, Install it on those devices, choose the same Zerotier network that you set up in BI, login to myzerotier dot com and check the "Auth?" box. Within a couple of minutes it will show in the "Last seen" box if it is working.
Yes.Is it only necessary to install ZeroTier on the one Blue Iris PC and the one iPhone I plan to use for remote access?
No.do I need to install it on every PC and device on the home subnet side of the Blue Iris PC?
No.Does the ZeroTier tunnel between the Blue Iris PC and the iPhone subject the other machines on my home network to security risks if they are not running ZeroTier?
You can probably get by using the WIFI for back connecting to the BI PC for using UI3 without any issues. But I am not sure how performant it will be for connecting to the internet and using ZT to your iPhone. The only real way to know is to try it. If it is not performant, then you could run another cable.- Regarding the dual-NIC setup for the Blue Iris PC, if I use the motherboard GB ethernet connection for the camera subnet, is it possible to use the WiFi adapter (802.11ax) for reach back to the home subnet? Will this provide sufficient bandwidth to connect to Blue Iris from another PC on the home network using UI3 and/or connect remotely to Blue Iris with an iPhone using the app? Or do I need to add a GB dongle on a USB 3.0 port to get the necessary performance? I am not using the home network WiFi for any other bandwidth intensive purposes. I'm really just trying to avoid running another cable to the location I plan to setup the Blue Iris PC. But I will if it is critical for performance and reliability.
If you go to the bother of running another cable, then instead of using an USB dongle, install an PCI network card. They can be had for $40-$50.
not recommend WIFI for any security critical operation.