Stands For: Dynamic Domain Name System
Definition: Dynamic DNS (DDNS) is a method or service that automatically updates the information in the Domain Name System, typically an A or AAAA record, in real-time. It provides a mechanism for a host with a dynamic (changing) IP address to associate itself with a static, memorable hostname.
Key Characteristics:
- Purpose: To solve the problem of connecting to devices that do not have a static IP address, which is common for residential internet connections. DDNS ensures that a domain name always points to the host’s current IP address.
- How it Works:
- A DDNS Client (software on a computer, router, or other device) periodically checks the device’s public IP address.
- If the IP address has changed, the client securely notifies a DDNS Provider.
- The provider’s service automatically updates the DNS record (usually an A or AAAA record) for the specified hostname to point to the new IP address.
- Relationship to A Records: DDNS is not a new type of DNS record. It is a service that manages existing record types. The record being updated is just a standard A record (for IPv4) or AAAA record (for IPv6).
Common Use Cases:
- Remotely accessing a home computer, server, or NAS (Network Attached Storage).
- Connecting to personal security cameras or IoT devices.
- Hosting a small game or web server from a home network.
- Allowing small businesses without a static IP address to have reliable remote access to their systems.
Usage Note: As of June 2025, DDNS is a very common service used for home and small business networking. Many consumer routers and network devices have built-in DDNS clients that support popular providers (like No-IP, Dyn, DuckDNS, and others). It provides a crucial link for making dynamic residential connections accessible from anywhere on the internet.