What, indeed. Yes, I have internal DNS servers. They are what handle the split horizons. How would one do split horizon without an internal DNS service?
Because I was responding to this comment you had made:
So what's your solution when you have a wholly private service that will never have a public v4 address, nor a publicly routable v6? How do clients get the address for a nice domain name without the addresses in public DNS?
Which, if you claim you use private DNS, you know you can indeed solve by only having the private records sit on your private DNS service that can only be hit by clients on the internal network. Without the architectural bad practice of implementing split horizon.
Mate, what on Earth are you talking about? A private DNS server that can only be hit by clients on an internal network, which differs from public DNS, is split horizon.
I could not have been clearer that the private DNS servers I use provide different results from public, for the same names, which is the split. Not all private DNS servers are split horizon, and nothing I wrote implies that that's my understanding. If that's what you've concluded, then you've either failed to comprehend what I've written, or you're a troll.