Home Assistant cannot find KNX Gateway after switch to VLAN

Configuration
1

Hi,

EDIT: have posted a screenshot of the working configuration in post #3

I just reconfigured my Network to use VLANs. HomeAssistant Core runs in Proxmox, everything is updated to the most current versions:

OS Version: HOme Assistant OS 8.2
Home Assistant Core: 2022.7.6

I am using the KNX device, which worked well before moving to VLANs. It’s also connected to an external MQTT Server which is on a separate VLAN and also works. (VLAN IDs 10/50/51)

enp0s18: 192.168.10.164/24 (Homeassistant UI, but currently also works on the other IPs)
enp0s19: 192.168.50.164/24 (KNX)
enp0s20: 192.168.51.164/24 (MQTT)

While MQTT works flawless, the KNX device configuration tells me it doesn’t find the KNX-IP Interface. But I can even ping it from the HomeAssistant Terminal. I tried setting the local IP in the KNX settings with 0.0.0.0 and 192.168.50.164. No difference:

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I double checked the connection, I also can ping HomeAssistant on it’s VLAN50 IP address. Restarting the HA VM between different settings also didn’t make a difference.

Do you have any hint what else to check for?
Thanks in advance!

2

You can’t find an interface anymore because multicast probably doesn’t work across the different networks. Configure the tunneling server manually. If NAT is involved check “route back”.

1 Like
3

Thank you @farmio - in fact it was only changing the multicast group setting to the actual IP interface IP. For anyone else running into this, this is the working configuration:

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4

This shouldn’t work :neutral_face:
Sending Multicast to a Unicast address seems kind of hacky and probably doesn’t work with every Ip interface.

If you want to connect to a fixed IP you should use “tunneling” instead of “automatic”. This will skip the (multicast) discovery process and connect directly.