DNS Blackout Drill: Diagnose the Internet Before Blaming the App

Participants walk into a deliberately broken web service: sometimes the app is fine, sometimes DNS is lying, sometimes TLS is the problem, and sometimes the browser cache is the villain. The goal is to build calm diagnostic instincts before changing code.

We will use dig, curl, browser DevTools, traceroute-style reasoning, and certificate checks to separate naming, routing, TLS, CDN, and application failures. Each round ends with a short incident note: what failed, what proved it, and what the next operator should do.