I'm not an expert on this, but know enough to know the KVM doesn't need its own IP. In fact, the KVM I replaced it with provides ethernet to both my machines (at the same time) without getting its own IP.
The network was active for both machines connected to it. And it had its own IP. So 3 MAC addresses in total. I didn't ever open it up. But maybe someone will be interested in buying one and exploring more.
The KVM didn't have any documentation on anything related to its network interface. I ran a port scan on it but didn't know if there was a way to log into it.
I recently discovered a similar concerning security issue with my KVM. In my case it was a pretty standard KVM for multiple machines to share a keyboard, mouse, and screen but also Ethernet. One day while looking at my home network I noticed the KVM had its own IP and was transferring GBs of data everyday. I quickly blocked it from my network. But having used it for a number of months I worried that with screen capture and access to all my input devices, someone could have gotten access to pretty much everything I use. I wasn’t able to figure out if any data was actually being sent off my network and I really didn’t want to put myself in any more risk so I just threw it in an electronics recycling bin. Pretty scary what a network connected KVM could maliciously do.
The book uses Scala & ZIO but intends to be more about the concepts of Effects than the actual implementation. I'd love to do a Flix version of the book at some point. But first we are working on the TypeScript Effect version.