WildCard Domains // BIND Config

Im sure this has been asked many times earlier also but I could not find any solution for this.

I want to make a default website available as soon as the clients change the name servers to my name server. So as soon as they put in

I would like to be able to show a page on their website without having to create a website or an alias for this. Is this possible in any way using VirtualMin?

If not, I think there can be a script to listen to failed queries on bind which can call a VirtualMin API to create an Alias for failed domain. But Im guessing this will still fail the first query which can be avoided if the above option is available.

Please advise.