An IP address ,which stands short for Internet Protocol address, is a unique identifier for your computer, mobile phone, or any device that is connected to a network. Each IP address is different, like a fingerprint, thus making tracking possible. When you connect to the internet, your service provider gives you an IP address. Then, when you visit internet sites, this address is passed on and registered. This way, if you do not use a VPN, it is possible to know where you visited online.