Every laptop, every PC, every smartphone, every router, and any other device that is capable of connecting to the Internet has its own unique “Internet Protocol address”, or IP address.

This is analogous to how every single phone in the world has its own unique phone number, or how every single location on earth has a unique address.

No two devices on the Internet may share the same IP address, otherwise a network routing conflict may occur, since the Internet won’t know which device to route traffic to.

IP addresses may be either public or private.

Therefore, the Internet Assigned Numbers Authority (IANA), which is the non-profit organization responsible for assigning IP addresses, has reserved the subnet for private use within home or business networks.

No publicly accessible machine on the Internet is allowed to have a IP address. This prevents unauthorized access and intrusions into your network, by keeping it “unlisted” and “private”.

For example, at home you may have several smartphones, tablets, laptops, and printers that are all connected to your home router on a private network. Each will typically be assigned a IP address.