How can you tell if someone Not at your address is all so useing your internet ?

Answer 1

Assuming you mean Wireless or Wifi? You should be setting security on your wireless router anyway, so that you can enjoy all of the bandwidth YOU are paying for.

Shut off the broadcast feature so your equipment doesn't let everyone know its out there. Set WEP or better security and if you select a passphrase, make a note of it in the Routers manual, so you can find it again when you add or change equipment.

As far as seeing is someone is using your equipment... I'd really have to know what router make/model you have. As blinking lights can mean almost anything. If you have a cable modem, any legitimate users on your block are going to drive your activity light, and there is no trespassing involved. Wherein if you have DSL, none of your neighbors personal activity will be picked up.

Maybe this would work? While monitoring your activity lights, take a metal bowl and cover your wifi routers antenna - with your laptop or computer off. If the activity comes and goes with the placement of the bowl, it may be very likely someone is enjoying internet access at your expense.