Virtualmin has this nice feature where you can enable dynamic host and virtualhost updates so when your ip changes virtualmin updates the ips in the virtualhosts definitions. Without this feature your sites would not work anymore if your ip changes and you would have to update the ips manually.
The problem with this feature is that it only supports the DynDNS service and not everyone is using this service to update their host when their ip changes.
I'm using my own dynamic dns service and the good news is that this service is using the same protocol as DynDNS so virtualmin needs little change in order to support it.
All I had to do was add a way of specifying the hostname and port of the dynip update server.
Here's the patch for virtualmin ( tested with 3.75 and 3.76 ) :