Preface
This article is translated from Chinese. Please excuse any unnatural phrasing.
Recently I worked on a project using both UniFi devices and Official Hosting, which means paying UniFi every month — honestly not sure it’s worth it lol
Then I ran into an embarrassing situation where I just couldn’t get the devices adopted no matter what.
Note: This article contains no screenshots as there were sections I couldn’t capture.
Main Content
The Management Network Must Be Directly Reachable
The network setup at the time was roughly:
untagged = mgmt
tagged = lan / server lan / iot
I had originally set up the first AP via a wired connection to the switch. To spare my back from crouching next to the electrical cabinet, I moved to a more comfortable spot and tried to continue the setup wirelessly.
Then I found I couldn’t get it working — devices were discoverable, but adoption kept failing no matter what. In the end I went back to the electrical cabinet, plugged in wired, and it worked.
The realization: once an AP connects to the switch, it gets its IP via the untagged mgmt VLAN, so when adopting you must be on the same L2 broadcast domain as the AP.
Why device discovery can cross VLANs remains a mystery — too lazy to fire up Wireshark.
Fallback Methods
https://help.ui.com/hc/en-us/articles/204909754-Remote-Adoption-Layer-3
Official Hosting does have some fallback adoption options.
One is to set DHCP option 43 or a DNS A record for unifi pointing to the controller IP (I haven’t tried this myself — might be a different record type?).
But dealing with that NEC router had worn me out, so I didn’t bother with this approach.
Another option is to SSH in with ui:ui@<ip> and run:
set-inform http://xxx.unifi-hosting.ui.com:8080/inform
Of course, another problem came up: some ultra-budget switches don’t support SSH, so this doesn’t work for those.
Fallback of the Fallback
I found a third-party tool that can push an adopt request directly to the device:
https://github.com/HostiFi/hostifi-device-discovery-tool-releases/releases
You can discover devices, click adopt, and in theory they should show up in the controller.
In practice, nothing appeared. Before wrapping up the job, I tried adopting all the switches as a last-ditch effort, then bowed apologetically and called it a day.
The Hidden Default Site
With Official Hosting, purchasing a license lets you split the controller into multiple virtual sites. Since I was working as a subcontractor, I didn’t have full controller access.
When I reviewed everything afterward, I wondered: could orphaned devices that tried to connect via the Inform URL end up sitting in some default site?
After thinking it over, I had a colleague check the Default site — and sure enough, all the switches I had tried to adopt with the HostiFi Device Discovery Tool were there. We quickly adopted them and moved each device to the correct site (Move To New Site), and that was that.
Conclusion
Honestly, avoid UniFi Official Hosting mode if you can — it’s just asking for trouble. And since there’s basically no documentation about any of this anywhere, here’s my writeup.
That’s all.
End