Dynamic DNS (DDNS) is a service that automatically updates the IP address associated with a domain name when the device's IP changes. It’s useful because most Internet Service Providers (ISPs) provide dynamic IP addresses, which change periodically. DDNS ensures that your domain name always points to the correct, up-to-date IP address without needing manual updates.

How It Works:
- A client (often a router or a device on your network) periodically checks its external IP address.
- When a change is detected, it sends an update request to the DDNS provider.
- The provider then updates the DNS records so that the domain name reflects the new IP.

Uses of DDNS:
- Hosting a website, server, or remote access service on a home network.
- Allowing consistent access to security cameras or smart devices via the internet.
 
Dynamic DNS is a convenient solution for anyone who needs a consistent way to access their home network or personal server despite having a changing IP address from their ISP.