Dynamic DNS service
This field selects what Virtualmin contacts when it detects that the system's IP address has changed.

The available options are described below.

DynDNS-compatible service
Updates a provider that implements the DynDNS update protocol. Enter the provider's update server in the adjacent field as a hostname or hostname:port. The default is members.dyndns.org, and the connection always uses HTTPS. The login, password, and full hostname fields are sent to the selected provider.
Virtualmin system
Asks another Virtualmin installation to update the hostname's DNS record. Enter that system's hostname in the adjacent field, using the hostname:port format if Webmin listens on a port other than the default of 10000, along with login credentials that can modify the domain.
Run external script
Runs the absolute path entered in the adjacent field. Virtualmin passes the new IP address, the configured hostname, and the previous IP address to the script as command-line arguments.
Don't update any service
Skips notification of an external service. Dynamic address detection and optional updates to local virtual servers can still remain enabled.