DNS
6 posts tagged with DNS.
How CDN, DNS, and cloud outages affect apps you use every day
Apps you use daily share fewer pieces of infrastructure than you'd think. When one of those pieces fails — a single CDN, a single DNS provider, a single AWS region — half the internet seems to break at once. Here's why, with the canonical examples and what you can do about it.
DNS vs SSL vs HTTP errors: what actually broke?
A broken page can fail at any of four layers — DNS, TCP, TLS, or HTTP. The error message you see almost never names the layer, but the layer is the entire answer. Here's how to tell them apart in under a minute.
Why a website can be down in one country but working everywhere else
The same URL can return 200 OK in Frankfurt and time out in Mumbai. Four mechanisms explain almost every regional outage — GeoDNS, CDN POP failures, BGP routing problems, and government-level filtering. Here's how to tell which one is in play.
Why your DNS change isn't propagating: the five timers that actually govern it
'DNS propagation' has nothing to do with how long it takes. There is no single timer. There are five separate caches between your registrar and your visitors' resolvers — and you need to understand all of them to predict the answer to 'when will the new record be live?'
clientHold, redemptionPeriod, pendingDelete: every state your domain can be in, decoded
Domains do not simply go from 'active' to 'gone'. They pass through a precisely-defined sequence of states — most invisible to the owner until something breaks. Here is the full lifecycle, the EPP codes that mark each step, and exactly how long you have to react at every point.
DNS propagation isn't a thing — here's what's actually happening
The phrase 'DNS propagation' is misleading. There's no synchronous global update. What you're actually waiting for is a million independent caches to expire — and that timing depends on choices made by you, your registrar, and every resolver in between.