Discovery crossing VLAN boundary

Configuration
1

HA v. 0.85.1
Discovery now crossing IP boundaries - my LAN is seperated into VLANs, HA has discovered devices on a different VLAN - they can’t be ping’ed from the HA device.
This wasn’t happening on previous versions of HA - so how is it now?

3

This isn’t a Home Assistant issue, this is a network configuration issue.

I would look at the settings on your switches and/or router to see what is allowing the traffic to cross the boundary.

4

Tried both ping and nmap - neither respond with addresses - so how does HA do a scan?

Firewall set to first REJECT then DROP, both have the same effect.

5

Is there a switch in play also?

scans the network in intervals for uPnP and zeroconf/mDNS services.

https://developers.home-assistant.io/docs/en/creating_component_discovery.html

6

Home assistant uses a related project netdisco for discovery. It uses many methods. See https://github.com/home-assistant/netdisco

Although it looks like this is changing https://github.com/home-assistant/netdisco/issues/230

7

Yep - found it - thanks

8

Problem is with Router (USG)
mDNS is reflected across all interfaces and VLANs
only way to prevent is disable multicast DNS.
So - yes - not a Home Assistant issue.