How can i find out who is using my internet?

[Bullszeye]

Hello,my internet has been so slow lately.There are 5 suspicios devices on the network,but i've been thinkign that it's just a bug . http://i.imgur.com/plvN4be.png the last 5 here.IS there any way for me to know which device is using how much internet?THanks.Im connected by ethernet btw,the 5 are prob by wifi

 

[RealBeast]

While you can't find out who it is, someone is connecting with their phones. Log into your router configuration pages, change your wireless security to WPA2/AES and enter a security passphrase -- write it down, you will need it for your wireless devices. Then save the settings and reboot your router, those devices should get disconnected.