Definition
Dynamic DNS (DDNS) is a service that automatically updates a domain name's DNS record whenever the underlying IP address changes. Most residential internet connections are handed a public IP that the provider can rotate without notice, which would otherwise break any domain pointed at a home server. DDNS keeps a stable, memorable name reliably pointing at a moving target, making it a staple for sovereign Bitcoiners hosting services from home.
How it works
A small client runs on your router or a device inside the network. It periodically checks the connection's current public IP and, when it detects a change, contacts the DDNS provider's API to update the matching A or AAAA record. Because the change happens at the authoritative level, resolvers around the world pick up the new address as their cached copies expire, governed by the record's time-to-live (TTL) value, which DDNS setups usually keep low.
Why it matters for self-hosting
Without DDNS, a home node reachable at node.example.com would become unreachable the moment the ISP reassigns the address, and you would have to edit DNS by hand each time. With DDNS, the name simply follows the address. This lets you point a personal domain at a Bitcoin or Lightning node, a wallet backend, or a dashboard and trust that it stays reachable.
Limitations
DDNS solves the changing-address problem but does nothing about address translation or carrier-grade NAT; a correct DNS record is useless if inbound packets are still dropped at the router. It also requires trusting the DDNS provider with update access to your record.
DDNS builds directly on the naming concepts in DNS, and is typically paired with Port Forwarding so the named service is actually reachable.
In Simple Terms
Dynamic DNS (DDNS) is a service that automatically updates a domain name’s DNS record whenever the underlying IP address changes. Most residential internet connections are…