Kurt "CyberGuy" Knutsson explains how to look up a phone number for free after seeing an unknown caller dialing you, and shares the specific services you can use.

A reverse phone lookup can reveal the name and address associated with a phone number. But beware of websites asking for your personal information.

A VoIP call is a phone call made over the internet rather than traditional phone lines. Yes, you can trace it—learn how to find the owner of a VoIP number.