Dynamic DNS Facts
With Dynamic DNS (DDNS), resource records can be created automatically on a DNS server. Without dynamic updates, all A (host) and PTR (pointer) records must be configured manually. With dynamic updates, records are created and deleted automatically. Dynamic DNS is required to support Active Directory.
A dynamic update occurs when a client modifies its corresponding resource record on the DNS server. Dynamic updates occur when:
- A network connection’s IP address is added, deleted, or changed.
- The DHCP server changes or renews an IP address lease.
- The client’s DNS information is manually changed using ipconfig /registerdns.
- The client boots.
- A server is promoted to a domain controller.
The default configuration for dynamic DNS is as follows:
- Windows clients (2000 and above) create their A records with the DNS server. Windows 9x/Me/NT clients do not support dynamic DNS.
- The DHCP server registers the PTR record with the DNS server for clients capable of dynamic updates. The DHCP server updates both the A and PTR records for clients that do not support dynamic updates.
- Dynamic updates must be enabled on the zone. By default:
- Dynamic updates are not enabled on primary zones. You can enable dynamic updates when you create the zone or modify the zone properties later to enable this feature.
- Dynamic updates are enabled on Active Directory-integrated zones. Note: When you convert a primary zone to an Active Directory-integrated zone, the current dynamic update setting is retained.
For Active Directory-integrated zones, you can choose to use secure dynamic updates. With secure dynamic updates, only domain members can create records, and only the original client can modify or remove records.