I have a HomePod mini that functions as a BorderRouter.
It worked very well for months... then recently had problems.
The HomePod is connected to the network and in HA with the integration Apple TV as follow:
the problem is that sometimes it disappears completely as a border router, sometimes it comes back and works, sometimes it comes back but the connected devices (Matter over thread) are offline.
I am using HA OS on my miniPC.
After several tests and resets, I may have figured out the problem:
I use two Fritzbox routers.
One is the main router and the other is connected via mesh networking (which extends the network with the same settings as the main one).
The HomePod is located between these two routers (Not far away but within a good radius for both) without ever losing connection.
I moved the HomePod closer to the main router, and now everything works.
There were no connection issues but when connecting to the mesh router… I don't know why it wasn't available as a Border Router.
Sounds like you have set up a double NAT'ing, which will cause issues.
Changing the second one to a AP only or set it in bridge mode will prevent the double NAT'ing issues.
Honestly, I don't know how to set it up as an AP. I use a mesh network on a Fritzbox and it automatically configures it as a repeater that is part of the same network... and it takes all the settings from the main router.
All other devices connected to the other router can be seen on the network normally… there is something wrong with the Thread Border Router
I do not know fritzbox that well, but it sounds like it might be set up correctly.
The fritzbox does not use NAT in the mesh, all devices are on the same subnet.
I have had issues where devices cannot connect to the Fritzbox mesh network, rebooting the fritzboxes always clear the problem.
