T-Mobile Home Internet Backup

I live in Florida. Florida has bad weather. You may have seen it on the news. Our home lost Internet (we get it from Comcast) due to Hurricane Milton, which isn't the first time. I've been looking for a backup Internet solution for some years now, especially as I work from home. Finally, T-Mobile has stepped up with a $20/month thing called T-Mobile Home Internet Backup. It's capped at 130G a month, but is otherwise identical to their regular 5G Home Internet service.

So I'm trying it.

And... I'm in two minds.

Let's start with the positives: it's fast. Very fast. I get around 400Mbps down, and 40Mbps up. That's close to Comcast for the downloads, and double (!) for the uploads. Latency is similarly comparable.

The main negative is that it's crude, uncustomizable, and isn't user friendly for its intended purpose.

The basic system is supplied as a combined 5G modem and router with no options. No, really. You can set the “admin” password but can't use it for anything, and determine the SSID and password to the Wifi network you create. But you cannot:

If you plug in your own router, it will do nothing to accommodate you. It won't turn off the Wifi. It won't give your router any IPv6 features (DHCP-PD is not provided, I'm not sure any IPv6 functionality is provided even if you connect directly.) You'll certainly have issues with certain types of application.

The unit does have undocumented features, you can download an app called HINT Control which will allow you to turn off the Wifi or restrict it to a single frequency band. If you're feeling more adventurous there's a web app you can install, if you have the environment to run it, that'll make it feel a little more like a regular router, called KVD Admin. The options though are the same as the above app. Advanced features such as port forwarding or IPv6 support are out of the question however.

It's marketed as a backup but it doesn't act like one.

I am a nerd, so I know my needs are more substantial than Joe Smartphone, but it's not clear to me that even users with simpler needs will find it anything but a jarring experience when used as a backup.

The ideal implementation for something like this would sit between someone's router and their home network. Unfortunately that's not generally practical, most people use a combined Wifi/router/gateway, which means you can't just slip something in that reroutes packets when the main Internet is down.

So T-Mobile's solution to this is essentially give up. Instead of putting in any effort at all into allowing end users to integrate the T-Mobile system into their existing home network. The apparent assumption is that you'll simply go through every single device you have – your laptops, your tablets, your smart TV, or any other “smart” devices (heaven help us) you rely on, your Alexa hub, your security camera, etc – and reconfigure them to use the T-Mobile wireless access point. And when the main Internet comes back up, you'll somehow notice and reverse that process and reconfigure every one of your devices back again.

How it should work

An end user, whether nerd me or Joe Sixpack, actually wants this to act more like a switch, where flipping one way means our Wifi router is routing Internet access via the regular route, and flipping the other way routes it via T-Mobile instead.

In an age when every ISP insists on sending customers preconfigured all-in-one boxes with limited customizability, it's tough to offer that in a user friendly way. But at the same time, you feel T-Mobile could have at least tried by providing a solution that meets the majority of configurations. One obvious way would be for T-Mobile's Wifi to be configurable as a pass through. People would connect to it by default, but instead of providing DHCP and routing to the Internet, it would normally pass packets on to the customer's gateway. When the switch is flipped however, it would intercept packets for the gateway and route them via T-Mobile instead.

And obviously, if you're like me, and want to use your own Wifi router, you could plug your router (and the rest of your network) into the T-Mobile box.

How I configured it

For now, my options are limited. I put an old router in front of the T-Mobile box to prevent its DHCP server from touching my network directly, and my ISC DHCP server (I don't use my router's) can be configured if needed to change the default gateway to that router should I lose access to the Internet via Comcast. I can also do it manually, or on a per-machine basis.

This is, to be honest, not ideal. It means every device has to be forced to renew its DHCP lease when there's an Internet issue. Some devices do this easily, I can get my laptop to get the latest information just by reconnecting it to Wifi.

A possible option would be to have an intermediary act as the default router, but I haven't yet figured out the best approach to doing that. It seems extremely inefficient.

Final thoughts

The system continues the industry's desire to control how we use the Internet and ensure it fits into the bizarrely limited world view of those who market ISP services. Which is a shame because the same desire for a “simple Internet” that “just works” also cripples T-Mobile's intended customer base for this specific service. You can't beat the price though, and if you're prepared to duct tape a bunch of kludges together, you can make it work.