I have an LIFX flood light. I added it as the only matter device in the integration and it worked fine.
My local network has IPv6 support, but none from my ISP, so it uses ULA addresses (and link local) and DHCP6 assignment, and HA has static IPv4 and IPV6 assignments.
I powered off, moved it, and it no longer works.
It is on the network – when I look at Device Info I get the IP and IPv6 addresses, and I can ping it with each from my desktop (same VLAN).
When go to the HA shell it shows me two IPv6 addresses, and I can ping both of those from my desktop, and can ping its IPv4 address also.
While in the HA shell (and I’m not at all sure I understand exactly what that is, container/network wise), I can ping the IPv4 address of the device but not the IPv6. When at that shell any IPv6 I ping says “network unreachable”, whether link local or ULA. And IP ADDR shows nothing IPv6.
But when I log in it shows the right addresses, e.g.
Welcome to the Home Assistant command line interface.
Home Assistant Supervisor is running!
System information:
IPv4 addresses for eth0: 192.168.130.254/24
IPv6 addresses for eth0: fd34:1727:2650:130::98e9/64, fe80::d327:3ecc:3840:87e1/64
OS Version: Home Assistant OS 16.2
Home Assistant Core: 2025.9.4
Home Assistant URL: http://ha.local:8123
Observer URL: http://ha.local:4357
System is ready! Use browser or app to configure.
[core-ssh ~]$ ping -6 fe80::d273:d5ff:de80:d2d8
PING fe80::d273:d5ff:de80:d2d8 (fe80::d273:d5ff:de80:d2d8): 56 data bytes
ping: sendto: Network unreachable
[core-ssh ~]$ ping fd34:1727:2650:130::98e9
PING fd34:1727:2650:130::98e9 (fd34:1727:2650:130::98e9): 56 data bytes
ping: sendto: Network unreachable
[core-ssh ~]$
I have no idea if it should work from this layer of the docker stuff. I am running HAOS by the way. The addresses shown on login are what were assigned statically. And I CAN ping them from my desktop on the same VLAN.
When I go to the matter integration and ping it says it pings IPv4 but not IPv6. Which is consistent with what I see from the shell prompt.
As I understand it since I’m on the same LAN no routing should be involved (but the router actually should work).
I feel like I’m missing some HA setting that is preventing it from being able to use IPv6 even though it’s responding to it, but I do not know where to look.
This is the HA setup for network:
All of those addresses can be pinged from my PC (same VLAN as device and same as HA). I have rebooted several times just in case (also the device).
I’m drawing a blank… any advice?
Linwood