# What is Dynamic DNS (DDNS)?

> Dynamic DNS (DDNS) is a method for updating Domain Name System records automatically when the underlying information changes.

- Canonical URL: https://yellowcube.eu/glossary/dynamic-dns/
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- Language: en
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## Content

In standards-based DNS, the DNS UPDATE operation lets an authorized client change zone records without manual zone-file edits. Automation can keep names aligned with changing addresses, hosts, and services.

The term also describes services that maintain a stable public hostname for a connection whose public IP address changes. Such a service may use DNS UPDATE or a provider-specific API. An updater detects the address, authenticates to the service, and changes the relevant record; resolvers see the change as caches expire or refresh.

### Key points

- **Controlled scope:** Update credentials should be authorized only for the zones, names, and record types that the updater genuinely needs to change.
- **Transaction protection:** Transaction Signature (TSIG) can authenticate a DNS transaction and protect its integrity between configured parties.
- **Operational reliability:** Monitor update failures, unexpected record changes, credential use, stale records, and the effect of caching when addresses change rapidly.
- **Important limitation:** DDNS is not inherently unsafe, but a compromised updater, provider account, credential, or overbroad update policy can redirect every user of the affected name. TSIG protects a transaction between its parties; it does not provide DNSSEC validation for later resolver responses.

### Related terms

[Domain Name System (DNS)](<https://yellowcube.eu/glossary/domain-name-system/>) · [Domain Name System (DNS) security](<https://yellowcube.eu/glossary/domain-name-system-security/>) · [Dynamic Host Configuration Protocol (DHCP)](<https://yellowcube.eu/glossary/dynamic-host-configuration-protocol/>) · [Domain Name System (DNS) hijacking](<https://yellowcube.eu/glossary/domain-name-system-hijacking/>) · [IP addressing: static and dynamic addresses](<https://yellowcube.eu/glossary/ip-addressing-static-and-dynamic-addresses/>)

### Sources

[IETF RFC 2136: Dynamic Updates in the Domain Name System](https://datatracker.ietf.org/doc/html/rfc2136) · [IETF RFC 3007: Secure Domain Name System Dynamic Update](https://datatracker.ietf.org/doc/html/rfc3007) · [IETF RFC 8945: Secret Key Transaction Authentication for DNS](https://datatracker.ietf.org/doc/html/rfc8945)

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