It was an interesting discussion, with lots of disagreement, but ever-growing consensus. After evaluating several options, one approach was clear—and, I must admit, somewhat embarrassing to Paul.
DJB was right. All those years ago, Dan J. Bernstein was right: Source Port Randomization should be standard on every name server in production use.
There is a fantastic quote that guides a lot of the work I do: Luck is the residue of design. Dan Bernstein is a notably lucky programmer, and that's no accident. The professor lives and breathes systems engineering in a way that my hackish code aspires to one day experience. DJB got "lucky" here—he ended up defending himself against an attack he almost certainly never encountered.
Such is the mark of excellent design. Excellent design protects you against things you don't have any information about. And so we are deploying this excellent design to provide no information.