Updated my network to Unifi Cloud Gateway Ultra and Unifi switches yesterday, replacing original router and switches. In the process I lost all of my Matter devices.
Hub has a new IP after the update, but I wasn't aware of a requirement for the hub to maintain a consistent IP to support Matter devices.
What have I forgotten...?
WiFi Matter devices? Or Thread? Are they still visible to the Matter controller they were commissioned on?
On that note, did the Matter controller change IPs?
As long as the devices are on the same network as the hub, the ip’s don’t matter… Now if anything with your WiFi settings changed, the devices might have to be re-configured.
When I rebooted my ASUS router I lost all my Matter Devices (3 MS600 sensors and 1 Tapo Dimmer). All what I had to do is in HE go to each Device Page and click on "Initialize" button.
After that event I did not have to reboot router again. So, I have no idea how consistent this failure is/was.
Do you have other Matter controllers that are able to use those devices?
Thanks, all, for replies...
They are all Matter/Wi-Fi devices. Tapo Matter plugs and Third Reality night lights.
I can still control the Tapo lights from Google Home, which was where they were initially set up before adding to the hub. I can also still control the 3rd Reality night lights from the 3rdR app.
Quick look at Unifi app showing the Tapo plugs - all have valid IPs:
The devices are on a 192.168.20.x subnet/VLAN, but I don't have any firewall rules, or other traffic control set up yet - I'm leaving everything wide open/unmanaged (default for new Unifi devices/switches) until I've confirmed things are working.
I've re-confirmed just now that I can see/access devices from my default network (192.168.1.0) where the hub is, to any device on 192.168.20.0, and vice-versa (e.g., put laptop on VLAN20 network it can access HE hub on 192.168.1.0 subnet). I can also control the Night Lights from the 3rd Reality app w/my phone on the default network w/the Night Lights on the 192.168.20.x subnet.
I did just now remove one of the plugs from the hub, removed it from GH, added it back to Google Home, but it won't re-join the hub, fails every time:
Everything else related to HE is working normally after updating the hub IP in a few integrations...
Hopefully that all makes sense...
Only other control options are Google Home and the 3rd Reality app, and both can still control the devices.
Yes, both the hub and the devices changed IPs as a result of the HW upgrade. I haven't seen any place where I would have to update Matter settings that the hub has a different IP...
Thanks, but this did not help me...
Bryan:
The hub definitely, and devices likely (don't have a record) changed IP addresses.
Can you confirm what you mean by "re-configured?" Remove/re-join the hub, completely remove re-commission, then re-join the hub?
So if your hub and matter devices are in different VLANs, have you enabled IPv6 for the subnet the hub is in?
And is IPv6 being routed between the two VLANs?
Recall that Matter device sharing requires IPv6.
He means if the devices cannot connect to the new Wifi the devices themselves would need to be setup again. SOunds like you used the same SSID and password though so they reconnected?
Does Matter rely on mDNS at all? That does not traverse subnets by default.
Is your Google Home on the same VLAN as the devices or the VLAN with your HE hub?
Also the TAPO app and 3rd app may not be relevant. I know the TAPO app uses some other API on the LAN and not Matter. Not sure what 3rd app des, if it uses matter or some other TCP/IP API.
Not to my knowledge. It is all IPv6 for sharing between controllers (AFAIK). Hence my comment.
Yes, SSIDs and PWs are unchanged, restored from a backup of my previous Unifi Network app setup. Same settings under which these devices were working previously. @aaiyar - I never had to enable any IPv6 settings when I added Matter devices to my hub months ago, so the necessary capabilities should still be there.
Google Home is on the same subnet/network as the devices, 192.168.20.x.
Thanks for the comments on the apps...Google Home is still able to control the devices so they do appear to still be normally connected.
Only the hub is on the default network (192.168.1.x), so maybe what I have to try is to move the hub to the 192.168.20.x subnet. Should't have to,as I've confirmed communication between both subnets is open in both ways...
But you have managed switches now ......
They were managed switches before as well, and the previous switches had VLANs implemented, tagged ports, etc.
The current switches can be managed but are currently left at their default out-of-box state, which is no management settings/VLAN configt, etc....they are basically behaving like "dumb switches" at the moment, which I think I've confirmed by showing open control/communication between the two subnets.
I would do that as a test to see if it fixes it.
With IPv4 or IPv6? Could be different results. Matter uses IPv6 only.
And if it does fix it, then the issue is with IPv6 routing. Or IPv6 is not enabled in the subnet that the hub is currently in.
The really odd part about the IPv6 discussion is that I never made any IPv6 changes on my network when I started using Matter, that's with the same access points/same access point configuration (restored from a backup from my previous Unifi Network app). So not sure why that would suddenly be an issue, other than the subnet the hub is on.
I know next to nothing about IPv6, and don't want to blow anything up by enabling it and leave the wife stranded/pushed offline or me locked out. 
So I'll get the hub moved back over to 192.168.20 subnet and see if that is the magic sauce required.
Download the Hubitat app
