Google Mini and Nest Audio devices all using strange IP address 32.1.28.2 reported by Unifi UDM SE

[aafaber]

This issue has been driving me nuts for weeks... Any help would be appreciated. I have to say upfront in all honesty that my Google devices appear to be functioning perfectly fine, but my nerd OCD is preventing me from dropping this issue.

On my Unifi UDM SE I see the same message every day "Multiple devices are using the same IP address:
32.1.28.2. Please check each device's configuration to ensure none are communicating with a rogue DHCP server."

There are some topics on Reddit and the Unifi forum, but I'm quite certain that my issue is an issue with my Google devices and not my Unifi device, which is why I'm asking for help in this forum.

I first contacted Unifi support. They helped me by showing me where to find the MAC addresses of the devices that are causing this issue. This can be found by downloading the support log file (currently found in the Network app under Settings, Control Pane, Console, Support File and then Download). Then in the log file you can find it in /unifi/logs/server.log by search on the IP address.

To my surprise it was only Google devices causing the issue up to 25 times per day (so in the normal interface the UDM summarizes the issue to one each day). And what's extra strange, is that it's only 3 Google Mini's (1st and 2nd gen) and two Nest Audio devices. My Nest Hubs are not in the log. Neither is any other device. It's usually two devices, sometimes three.

The devices are not actually using the IP that starts with 32 (or perhaps they're using it briefly), and my DHCP is not giving out IP addresses in that range. They're getting an IP address in the 192.168.1.X range. They're not set to use a fixed IP address either. 

I have contacted Google support but that didn't lead anywhere. The support agent said it had to be Unifi, but that doesn't make sense to me. I have reset a Google Mini to no avail and restarted the UDM and the Google many times. At some point I was taking part in the Preview program of Google Home but I have switched that off.

The issue started beginning of this year. It's difficult to see if there was a firmware update to the Google devices at that time because the Google firmware page doesn't have any history or release dates. I notice now that Nest Hubs are using a different firmware than all the other devices, which share the same firmware.

Does this sound familiar to anyone? Any help would be appreciated.

[bvandendries]

I can only confirm I have exactly the same issue since January 15th 2025, but in my case the IP address is 42.2.164.113. Have you found out anything else in the meantime?

[aafaber]

That's so interesting! In a way I'm glad there's someone else with this issue... 😃 and strange that it's a different IP-address. 

For a moment I thought I solved it by re-starting all devices at once because the issue was gone for at least a day. I figured perhaps before restarting the devices had kept the firmware of the preview-release. But then the issue re-appeared. 

Today, there's another interesting thing happening in that the issue has stopped since last night. I'm not seeing the errors in the log after 23:00 of February 23rd. But it's probably too soon and it will re-appear later. Will let you know.

I noticed the preview firmware is now different than the stable firmware for the Google Home devices. I'm not entirely sure if I was on that firmware before. My next thing to try (assuming the issue re-appears) is activating the preview program again to see if the new firmware has a fix.

edit: indeed too soon, at 5 in the morning the conflicts started again after skipping a full day. I've now enlisted in the preview program but not sure how to get the firmware to upgrade to the preview release. Perhaps it will update overnight. btw I think my issue also started mid January.

[aafaber]

I've also noticed in my Home Assistant log that the each of the Google devices regularly loses connection. It always seems to be at night and once per day. I suspect they're restarting themselves without making the chime sound and at that point perhaps they get the strange IP address, however the timestamps in the log from Unifi and HA are not exactly the same.

[aafaber]

Preview firmware 3.75.456944 doesn't solve the issue unfortunately.

[bvandendries]

That's too bad :-(. I also still have the issue but I have noticed that my LG Soundbar also gets this strange ip besides my Google Home Mini speaker. 

[aafaber]

Very interesting... Different IP than the Googles? 

[bvandendries]

No, they get the same IP address: 42.2.164.113. When I examined my Unifi log files the duplicate IP warning is because both my Google Home Mini and he LG Sound Bar get this IP. Still not sure why this is, but the only thing both devices have in common is that they can act as voice assistants.

[aafaber]

If it's also a Google Home voice assistant perhaps they're using the same code.

btw I've also enabled "Rogue DHCP Server Detection" on the Unifi UDM but it's not making a difference.

[bvandendries]

I have also enabled the Rogue DHCP detection but no difference on my side as well. As a test, i disconnected my Unifi router (that also acts as the DHCP server) and tried to obtain an IP address to rule out the presence of another (rogue) DHCP server. I did not get an IP address, so I think it's safe to say there is no rogue DHCP server at play here. 

[Blooest]

Same thing happening here, but I have a total of 10 different MACs grabbing the single IP 38.1.2.134. Six of those are Google Home/Nest devices, one is a Pixel Watch, and one is a Lenovo smart clock, itself effectively a Google Home, but the interesting thing is that the remaining two are an Apple HomePod Mini and a Raspberry Pi. That last one in particular has utterly baffled me because I definitely never configured any sort of static IP on that RasPi and it certainly wouldn't have been a Cogent external IP if I had, nor are any of the several other RasPis I have deployed exhibiting the same behavior.

[aafaber]

That's quite bizarre, I also assumed this would be limited to Google Home devices. I have one active RPI with Home Assistant on it but it's not picking up the weird IP address.