If I understand correctly, the author presents a case for securing DNS by moving away from a shared directory toward application-specific directories. At the end, he takes a sharp turn to worry that such a move will tear apart the openness of the internet. I suppose an analogy is moving from phone numbers, with shared telco-managed directories, to chat apps managing their own directories. You can’t contact me on Instagram with my HN handle because they don’t use shared directories.<p>Ok, but there are more important reasons. Walled-garden directories is a symptom not a cause. For that matter, SNI and path-based load balancers are examples of the application-level address resolution overlay already in practice. Those techniques merely implement, not drive, balkanization.<p>Basically, application-layer DNS doesn’t pass the “but for” test. As in, it is not correct to say “but for application-layer DNS, Facebook/WeChat/Google couldn’t build walled gardens. With it they can.”