Can a secondary ethernet port in a HAOS Mini PC be configured to directly interface with an alarm panel ethernet?

Installation Home Assistant OS
1

Background: I would like to build a new Home Assistant system which interfaces with a new alarm system using a dedicated Home Assistant Mini PC. Ideally, I would like the HA system and alarm system to be able to operate independently in case either were to fail, however I have not found an independent alarm system (reasonable cost in the US, without Cloud service) that easily interfaces with HA that meets my needs. The closest I have found is the Konnected Alarm Panel Pro local alarm, however it only has 12 inputs. The next best option I found is the Hornet Nest Alarm Panel on Crowd Supply (Hornet Nest Alarm Panel | Crowd Supply) - unfortunately, its current firmware does not contain the alarm logic and state machine to operate as a stand-alone alarm system, thus currently requires Home Assistant to host this additional functionality via Alarmo (or similar). For robustness and isolation (ie. UPS backup, network issues, etc.), I would like to connect the Hornet Nest Ethernet one-to-one directly to the HAOS Mini PC secondary Ethernet port.

I already have a dedicated HAOS Mini PC that has two Ethernet ports:

I assume that HAOS may not natively be plug-n-play whereby one Ethernet port automatically is a client establishing a connection from a DHCP server on the primary network port and the secondary port would automatically connect directly with the Hornet Nest panel Ethernet port without additional configuration.

How do I configure HAOS to utilize this secondary Ethernet port to interface directly with the Hornet Nest panel Ethernet port?

Is an Ethernet crossover cable required?

Is it possible to configure HAOS such that I can access the Hornet Nest panel on this secondary port from other devices on my primary network (port forwarding?) on a fixed IP outside of my primary network’s assignable DHCP range (eg. 192.168.0.250)?

2

Crossover cables are in 99.99% of usecases a thing of the past.

3

Hi, a suggestion: have you considered using your HA as an alarm system with the use of [Custom Component] Alarmo - browser managed alarm system ?

If you HA has sensors to detect presence, opening of doors/windows and if you use the companion app on mobile, you already have everything to use silent alarms.
On top of that you could add a siren and a keypad to have a system that can be updated and you don’t need to install another set of sensors.

Some might advice against it and sometimes you need a proper, certified system for insurance.
If not and your HA is stable/reliable, I don’t see any other advantage for a dedicated alarmsystem.

4

Yes, as I noted, I would probably use Alarmo.