This page allows you to setup Virtualmin to detect changes to the systems primary network interface, and update a dynamic DNS entry when it changes. This is useful if you are running Virtualmin on a system with an address that occasionally changes, such as one running on in a virtual machine environment like Amazon's EC2. It is also useful for servers that are connected to the Internet via a connection without a fixed IP address, such as ADSL or Cable.

To use this page, you must select a dynamic DNS service, enter the hostname used by your system on that service, and also the service's login details. By default, Virtualmin will look at the IP address assigned to the primary network interface (like `eth0`) to check for changes, but if your system is behind a NAT router you should select the Address visible from the Internet option to have it discover the IP that the rest of the Internet really sees.

When a change is detected, all virtual servers with shared IP addresses using the old address will be updated to the new one. This change will be made in both the Apache configuration and DNS records.

If the `External script` service is selected, you must enter the full path to a script into the adjacent field that will be called when the system's IP address changes. The new IP and hostname will be passed to the script as command-line parameters.