You need to get some expert help with your router. If you don't lock it down, anyone nearby in the neighborhood will piggy-back off your ISP connection. Best way is by hidden router name that only you know and can type into your computer in initial connection, along with a strong password. Additionally, you can limit the number of connections allowed to a small number. Additionally you can only allow a small list of IP addresses to connect, that you type into your computer rather than have the router randomly assign an address (if you are real paranoid).
Thanks, Roadcat, for that advice. There is a program I once downloaded that tells how many users are connected to your router. Another program measures whether your internet co. is actually providing the speed you pay for.
no, no..... it is secure. I had to log each of the devices on to the net work. It is a linksys router
But not to worry..... in my neighborhood is a wi fi signal entitled FBI surveillance van 2 , so I think bad guys will stay away.