Unbound dns. It worked perfectly and all that jazz. But one day it didn’t. No one could answer why. Every solution in book was tried. Got support from high up but nope. Gave up for the day then two days later it just worked.
For three years then same problem and no way to fix it. And I gave up. Really liked it and one day I will try again but rebuilding my network every time really sucks.
The problem is ai needs work to train on.