custom LAN IP or DHCP range

[SimpleSimon23]

I have a BT SmartHub connected to the internet.  I have a 3 unit Nest wifi Pro system with main unit connected by ethernet into the BT box, and the other ethernet to a remote Nest wifi unit.  The 3rd unit is wifi only.

The BT box creates an IP network 192.168.1.xxx to which some devices are attached by ethernet via switches etc.

The Nest wifi unit creates an IP network 192.168.86.xxx to which many other devices are attached wirelessly.

Apple Home is on my iPhone (up to date iOS) but Ikea Tradfri smart gateway is attached by ethernet to BT box, and Tado heating controls are attached to BT box by ethernet.  Now Apple Home cannot control any Ikea or Tado smart devices.

I tried to change the Nest IP address and range but to no effect.  Even Google support could not help and blamed my ISP.  Now I know that it is not possible, but why is it an option?  Why did Google support not tell me that what I was trying to do would not work on this system?

Would it help if I put all the devices on the BT hub onto a switch connected to the Nest unit?  At the moment the "out" ethernet from the Nest goes via switches to a remote garden situated Nest unit.  If I put a switch with other devices attached between the Main nest and the remote nest, will this cause problems?  Might it resolve my comms issue between Apple Home, Google Home, Alexa and the various smart home devices?

[MichaelP · Accepted solution]

Hello @SimpleSimon23 

You can use a custom LAN IP range, but it can't be the same one that is already being used on the "outer" network – the one the primary Nest WiFi Pro unit's WAN Ethernet port is connected to (i.e., the one created by your existing "outer" BT SmartHub router, numbered as 192.168.1.xxx for your network).

But, you're on the right track with your proposed solution – connect everything to the "inner" network created by the primary Nest WiFi Pro unit through it's LAN Ethernet port. You can use multiple Ethernet switches to make enough ports available in the right places for this. Just stick to simple, inexpensive, unmanaged switch models (avoid "smart" or "managed" switches). Your primary Nest WiFi Pro unit should be the only thing directly connected to your BT SmartHub after this change.

You may need to reboot a few things to get them to acquire new IP addresses from the "inner" network address space (192.168.86.xxx). But, after that, everything should work, and all the wired and wireless devices should be able to see each other. 

[jaylaw64]

One amendment to this Answer that I encountered when setting up a similar network that I thought I would post here for posterity and save others headaches...

In the Google Home App, on your primary device, go to "Network Settings" -> "Advanced Settings"  -> "Lan Settings" and change the  "Router LAN IP" and "DHCP Pool" to your new values, press the "Save (disk icon, upper right)".

**** If you immediately return to the Lan Settings the new values will not be shown!! ****

Reboot your primary device (I just power cycle it). The new values will take effect. If you revisit "Lan Settings" you will see them now.

[SimpleSimon23]

Thanks Michael - I did follow through with my plan and it worked.  I appreciate your confirmation.

BTW - all the information I received from Google support was wrong and way off track so I won't be asking them for help again!

[vayvanne]

I suggest to switch the nest wifi pro into bridge mode.

[MichaelP]

Hello @vayvanne 

Since this user has a multi-node Nest WiFi Pro system with a mesh interconnect, putting the primary Nest WiFi Pro in bridge mode is not an option. That is only possible with a single-node (non-mesh) system. That said, this user is dealing with double NAT, and that will continue to be the case after making the change to have everything connected to the "inner" network. If this is a problem, the best solution would be to put their "outer" router (BT SmartHub) in bridge mode instead.

[vayvanne]

Did not know that google mesh does not work in a bridge mode. I honestly thought that it works, as I have 3-node network of other vendor which just does and the nodes are not even a routers - these are APs. Disappointed. Famous google engineering does not present in here at all. Hardcoded wifi channel, incompatibility between nest wifi /pro 6e, and now this. As I can understand these are just software limitations. Hey, google, dare to fix them?

[SimpleSimon23]

... and I cannot put the "outer" router into bridge mode - not available for consumer product from BT whereas it IS an option (I think) for business BT products.

[Rodneyraul]

Ensure all devices are on the same subnet by setting Nest Wi-fi to the BT Smart-Hub subnet. Try changing the Nest Wi-fi IP address and range to match the BT Smart-Hub subnet. For example, set the Nest Wi-fi to use the 192.168.1.xxx range. Check if Nest Wi-fi supports Bridge Mode to unify the network and eliminate conflicts. Connect devices requiring communication directly to either the BT Smart-Hub or Nest Wi-fi. Place switches carefully, avoiding the creation of separate subnets. Check for prioritization or port forwarding settings on Nest Wi-fi and BT Smart-Hub. Simplify the network temporarily by removing unnecessary switches for troubleshooting. Ensure all devices have the latest firmware/software updates. magical boost

[SimpleSimon23]

Thanks - see previous posts.  I have 3 Nest Wifi Pro units.  It is not possible to use Bridge Mode and it is not possible to set Nest Wi-fi to the BT Smart-Hub subnet.

It is resolved by putting ALL devices on the Nest Wifi Pro subnet by connecting ONLY the Nest Wifi Pro to the BT Smart hub.