I used nmcli to create a virtual interface on my Home Assistant machine so HAOS can send/receive traffic from both, LAN and IoT networks, and circumvent mDNS and AVAHI discovery issues. I only allow phones, personal tablets, and gaming consoles on my main LAN, while everything else sits in an IoT network (both use vlan). I didn’t want to allow firewall access from my IoT to LAN while my HA machine sits on the IoT network and even though I allow access for LAN to see IoT, mDNS and AVAHI discovery was extremely fickle. I tried setting up reflectors, but couldn’t get it to work. Doing the virtual interface was very easy to setup and I never have to worry about what device sits on what network for HA to discover or mess with my firewall to allow traffic or open ports between the networks. YMMV. The only other thing I had to do was define a different hostname to the IoT IP address for HA in the router. I also went the extra mile and setup CrowdSec and Firewall Bouncer add-ons for more security. More info here - Configuring VLAN adapters on Home Assistant Yellow - #5 by justynnuff