Using T-Mobile Cellspot Safely

The T-Mobile Cellspot is a miniature Cell Tower for your home. If your cell service is bad at your home or other location and you are a T-Moble customer, they will “Give” you a Cellspot to use with a “Return Fee” in case you don’t eventually return it to them.

I don’t know for sure, but I think it uses the same protocols as the “Real” cell towers employed by T-Moble. The reason that I am guessing this is because the device requires “Open Ports”, which is a problem for most modern routers. Modern Routers do not “Open Ports” but rather use “Port Forwarding”. Here is the support page for the CellSpot. Notice the list of UDP ports that are required to be open.

“Open Ports:” mean that the firewall does nothing with traffic on those ports. The traffic passes directly onto the LAN – local area network. Modern routers do not support “Opening Ports”. Instead they support “Port Forwarding”.

“Port Forwarding” which modern routers provide, establishes a relationship between one or more LAN addresses and arriving packets with certain port numbers. This allows the router to know that the incoming packets are to be “forwarded” to the desired devices. This is not necessarily secure. And certainly “Open Ports” is not secure, since it allows attackers on the WAN – wide area network – to get up to any kind of mischief in attacking your home network.

And at this point your eyes are probably glazing over. Rather than showing your how to set up Port Forwarding on your router, or struggling with your ISP to do that, which they will probably refuse to do. Xfinity has no way to “Open Ports” in their router for you, apparently. This article provides another way to use the Cellspot.

In the following discussion I’m using Xfinity as an example of an ISP. The same discussion and requirements will apply regardless of your “Broadband” provider, whether it’s Cable, DSL or Fiber. Click on images below for a larger view and click on the X at the top right to close the image.

Continue reading “Using T-Mobile Cellspot Safely”