Looking for Help with NetAlertX Discovering Multiple Networks

[raptor260]

Hi everyone,

I'm hoping someone in the community can point me in the right direction.

My Setup
Hardware: Raspberry Pi 5
Operating System: Home Assistant OS 18.1
NetAlertX Version: 26.7.1

Network Configuration:

eth0 is connected to 10.10.1.0/24
Home Assistant has a virtual IP of 172.30.33.1

From the Home Assistant console, I can successfully ping:

Gateway: 10.10.1.1
Second network gateway: 10.10.5.1
The Issue

NetAlertX is only discovering devices on the 10.10.1.x network. It does not discover any devices on the 10.10.5.x network, even though Home Assistant has connectivity to that network.

What I've Tried
Added 10.10.5.x as a second IP address in Home Assistant.
Looked for a way to run Home Assistant in host networking mode, but I haven't found an option for Home Assistant OS.

Has anyone successfully configured NetAlertX to discover devices across multiple subnets in a Home Assistant OS environment? If so, could you share your configuration or any suggestions on what I may be missing?

Any advice or ideas would be greatly appreciated. Thanks in advance for your help!

[raptor260]

Adding more information, I have TP-Link Smart home devices, 1 on the 10.10.1.x and 1 on the 10.10.5.x networks, HA is able to see both of those devices.

[jokob-sk]

Hi,

Thanks for posting your question.

Could you clarify what you mean by:

"Home Assistant has connectivity to that network."

If you mean that Home Assistant can successfully ping devices or the gateway on 10.10.5.0/24, that doesn't necessarily mean NetAlertX can discover devices on that subnet.

The reason is that ping operates at Layer 3 (IP), while discovery methods such as ARPSCAN operate at Layer 2 (Ethernet) and generally cannot scan across routed networks. Being able to reach a subnet via ping is therefore not enough for ARP-based discovery.

This documentation explains the limitations and the available approaches for monitoring remote networks:

https://docs.netalertx.com/REMOTE_NETWORKS/?h=ping

Also, when you mention that Home Assistant can see routers or devices on the other subnet, that's likely because those integrations (for example, TP-Link or other vendor integrations) communicate directly with the device over IP rather than performing Layer 2 discovery. That's a different mechanism than ARPSCAN.

Hope above helps to clear things up,
j