Where are IP addresses used?
IP addresses are used all over the web. After all, they're vital when you need an internet connection between 2 computers. Every computer, server or network appliance on internet has its own unique IP address so an online connection can always be made between 1 point and another unique point.
Besides the public IP address, which is known to the public, computers can have their own internal IP address. The internal IP address is not known to the outside world, but can be used to communicate between computers within a local network.