Google Nest Wifi With BT: How to Set It Up Properly (and Fix Double NAT)

You've added a Google Nest Wifi mesh system to your BT broadband, and something isn't right: the Google Home app warns about double NAT, games show NAT type strict or moderate, smart devices can't be found, a work VPN keeps dropping, or phones hop between the BT Smart Hub's Wi-Fi and the Nest Wifi. It usually works "well enough", but it isn't set up the way it should be.

The cause is that the BT Smart Hub and the Nest Wifi are both acting as the router. Only one of them should. Here's the right setup for this exact combination.

Why BT Is Different

BT's Smart Hub has no modem mode, so you can't simply hand everything over to your mesh. There's a second catch: BT Digital Voice, BT's home phone service, plugs into the back of the BT Hub. If you remove the Hub, the home phone stops working. And if you're not on full fibre, the BT Hub is also your modem, so it has to stay.

Option 1 (Most Homes): Nest Wifi as Router, BT Hub's DMZ

Normally the answer would be to put the mesh in bridge mode. But in bridge mode, Google Nest Wifi and Google Wifi only work as a single unit. Any extra points stop working, which defeats the point of mesh. So instead:

1. Connect the main Nest Wifi router to the BT Hub with a network cable, and leave it in router mode.
2. Open the BT Hub settings at 192.168.1.254 and turn off the Hub's Wi-Fi.
3. In the Hub's advanced firewall settings, set the DMZ to the Nest Wifi router. This passes traffic straight through and fixes most double NAT problems with games and VPNs.
4. Restart the Nest Wifi and check everything connects.

It's still technically double NAT, but with the Hub's Wi-Fi off and the DMZ set, most homes never notice. BT Digital Voice keeps working.

Option 2 (BT Full Fibre, No Digital Voice): Replace the Hub

On BT Full Fibre, there's an Openreach fibre box on the wall. If you don't use BT Digital Voice, or you've moved your phone to a mobile or another service, you can connect the main Nest Wifi unit straight to that box and remove the BT Hub:

1. Connect the main Nest Wifi unit to the fibre box's network port.
2. In the Google Home app's advanced networking settings, set the WAN connection to PPPoE and enter the login details. BT uses a standard login that's widely published: username bthomehub@btbroadband.com with the password BT.
3. Restart, and check you're online.

This gives the cleanest setup, with every Nest Wifi feature working. But remember: no BT Hub means no BT Digital Voice home phone.

Still Not Right? Quick Checks

• Two Wi-Fi networks? If the BT Smart Hub's Wi-Fi is still on, devices may join it instead of the Nest Wifi. Turn it off, or give it a completely different name.
• Restart in order: the BT Smart Hub first, then the main Nest Wifi unit once the hub is online, then the other units.
• Main unit next to the hub, connected by cable. Other units about halfway to the weak areas, not in them.
• Use cables between units where you can. Wired connections between mesh units give much better speed than wireless.
• Smart plugs and cameras won't connect? Many only use 2.4GHz. See smart device won't connect to Wi-Fi.

How We Handle It

Getting Google Nest Wifi and BT working properly together is one of the most common jobs we do. We choose the right setup for your line and home phone, configure the hub and mesh, place the units for full coverage, use cables between them where possible, and make sure gaming consoles, VPNs, cameras and smart devices all work, tested in every room. See our Wi-Fi and home networking service.

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