How do I set up my house internet to turn off wifi to selected cell phones in the house.?

[Markus Imhof]

As Gordon said. It all depends a bit on which router you have - you'll need to get the manual for the router, usually from the manufacturer's website.

Then you'll usually need a PC connected to that router via ethernet cable - you want to access the administration functions of that router, and these are (should be, anyway) usually only accessible through the local ethernet port(s), not through WiFi.

And finally you'll need the user ID and password for the router - often, the default ID/password can be found in the user manual.

Then you need to log into the router - which IP or name you need to use is also found in the manual. Any address in the 192.168.x.x range is possible - I've seen x.x = 0.1 and 1.1, others apparently prefer the high end numbers like 255.1. http://www.routerlogin.net/ also works for my router.

Now, you'll need to go through the router configuration until you find the settings for MAC filtering. It's easiest if you have all devices that you want to permit access for connected at that time - just set the MAC filter so that only these devices are permitted access. Any other devices that are not currently logged in (like your child's phones) will be denied access.

However, if the contract for your child's phone does permit cellular internet access (most of them do - and some of them charge high fees), that will block them for about 5 minutes.

Less if they're bright enough.