What the box in the hall is doing, join a network on your own, and recognize the one that is pretending to be yours.
The router has three jobs, and it does all three at once, quietly, for years at a time.
Key points
The router is your front door, your sorting office and your radio mast in one box
Switching it off and on again is the safe first move — nothing is stored on it
Network names are typed in by whoever set them up — two similar names means one is false
Position beats settings: high, open, and near the middle of the house
What to remember
A network name is typed in by whoever set the network up. Anyone can type anything, including your neighbor’s name, or yours.
When two networks have nearly the same name, one of them is lying. The desk knows which.
Height, open air, and the middle of the house. Those three things are worth more than any setting.
Try this
Go and read the sticker on your own router. Write the network name and password on a card and put it in a drawer, so the next visitor who asks does not send you crawling behind furniture.