How a network hands out an address
A device joining a network needs an IP address before it can exchange ordinary traffic. With DHCP—the Dynamic Host Configuration Protocol—it starts by asking the local network for configuration. A DHCP server, often built into a home router, responds with an available address and other settings, such as the router to use as a gateway and the addresses of DNS servers, which translate website names into network addresses.
The exchange is a short negotiation: the device requests an offer, then confirms the one it will use, and the server acknowledges the assignment. This helps the server keep track of which addresses are in use rather than letting two devices claim the same one.
Why the address is temporary
An address is usually granted for a limited period called a lease. While the device remains connected, it can ask to renew that lease. If it disconnects and does not renew, the server can eventually make the address available again. That recycling matters because a network has a finite pool of addresses, while its devices may come and go throughout the day.
The tradeoff is convenience versus permanence. Phones and guest devices can join without anyone configuring them, but a device may receive a different address after reconnecting. For equipment that needs a predictable address—such as a printer or a server—an administrator can often reserve one for that device. The result is a network that can seat everyday devices automatically while still keeping important equipment easy to find.
