dns

I used to think DNS was boring. You ask for a name, you get an IP, the application connects. That was my entire mental model, until a bug dismantled it completely. The service worked when addressed by IP but failed with a hostname. It worked from one machine and failed from another. Then, oddly, it started working the moment I added a trailing dot to the domain name. That day I learned that DNS is never simple, not because it is poorly designed, but because decades of accumulated behaviour are hiding behind what looks like a plain string....