It quietly tries to reach a few well‑known adult, gambling and proxy websites from your browser. If the Wi‑Fi's filter stops them, they're blocked. If they load, they get through. Nothing appears on screen and nothing is saved.

Kids are online wherever they are. A phone or tablet set up with a filter stays filtered anywhere, but a friend's TV, computer or game console uses that home's Wi‑Fi. The test takes 20 seconds and needs no sign‑up, so it's easy to send to the other parents. See our sleepover guide.

Sheepdog Filter is free for families. Change one setting on your router, or set up each child's device, and adult sites, gambling and proxy sites are blocked in about five minutes. Start free.

No. It checks the connection this device is using right now, so run it while connected to the Wi‑Fi you want to check. To cover a phone on mobile data, set the filter up on the phone itself. First phone checklist.