TP-Link Deco With BT: How to Set It Up Properly (and Fix Double NAT)

You've added a TP-Link Deco mesh system to your BT broadband, and something isn't right: the Deco 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 Deco. 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 Deco 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): Deco in Access Point mode

1. Connect the main Deco unit to the BT Hub with a network cable.
2. Switch the Deco to Access Point mode. In the Deco app, go to More > Advanced > Operation Mode and choose Access Point. The Deco restarts and stops routing.
3. Open the BT Hub's settings at 192.168.1.254 (the admin password is on the Hub's card), go to the wireless settings and turn off the Hub's Wi-Fi.
4. Restart the Deco and check every room.

This works on any BT broadband and keeps BT Digital Voice working. In Access Point mode some Deco features, such as parental controls and QoS, aren't available, because the hub is doing the routing. Set up parental controls on the hub or on children's devices instead.

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 Deco unit straight to that box and remove the BT Hub:

1. Connect the main Deco unit to the fibre box's network port.
2. In the Deco app's Internet connection settings, choose 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 Deco 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 Deco. Turn it off, or give it a completely different name.
• Restart in order: the BT Smart Hub first, then the main Deco 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 TP-Link Deco 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.

Related Reading

• Mesh Wi-Fi With a Virgin, BT or Sky Hub: All Combinations
• TP-Link Deco With Virgin Media
• TP-Link Deco With Sky
• Amazon Eero With BT
• Google Nest Wifi With BT