First of all, I'm not that into DNS, so maybe the answer to this question is very obvious, sorry in either way.
What I want is this: A DNS record which catches all non-existing subdomains on my site and link them to the external address of my site.
So, not to my internal IP address, but to my external hostname. I'm using CloudFlare and want to hide my server IP to the public, by setting it behind CloudFlare. When doing a ping then brings the IP of CloudFlare.
www.example.com -> www.example.com existing-subdomain.example.com -> existing-subdomain.example.com non-existing-sub.example.com -> www.example.com (and NOT the internal IP)
So then when somebody tries to fetch the IP with tracert or http://www.hcidata.info/host2ip.cgi for example they would not get to see my IP.
It doesn't necessarily have to link to my homepage, I would be very happy if there's just no way to see my server IP via such non-existing subdomains.