An IP address is the numeric identifier that lets a device send and receive data on the internet. Without it, no request would know where to return: it is the equivalent of a home address in a delivery network.
How it works in practice
When you open a website, your device sends a packet with a source address and a destination address. Routers use that information to forward each packet to the server and to bring the response back. The source address is your public IP, assigned by your provider.
The main types
- Public IP: identifies your connection on the internet and is visible to any online service.
- Private IP: used only inside your local network, such as 192.168.0.10.
- Static IP: stays the same over time, common on servers.
- Dynamic IP: changes periodically, the default for residential connections.
IPv4 and IPv6
IPv4 uses 32 bits, about 4.3 billion combinations — a pool that is already exhausted. IPv6 uses 128 bits and allows a practically unlimited address space. Both coexist today, and many providers still deliver IPv4 only.