Doug Jacobson in The Conversation:
When millions of people suddenly couldn’t load familiar websites and apps during the Amazon Web Services, or AWS, outage on Oct. 20, 2025, the affected servers weren’t actually down. The problem was more fundamental – their names couldn’t be found.
The culprit was DNS, the Domain Name System, which is the internet’s phone book. Every device on the internet has a numerical IP address, but people use names like amazon.com or maps.google.com. DNS acts as the translator, turning those names into the correct IP addresses so your device knows where to send the request. It works every time you click on a link, open an app or tap “log in.” Even when you don’t type a name yourself, such as in a mobile app, one is still being used in the background.
To understand why DNS failures can be so disruptive, it’s helpful to know how the Domain Name System is constructed. The internet contains over 378 million registered domain names, far too many for a single global phone book. Imagine a single book containing every American’s name and phone number. So DNS was intentionally designed to be decentralized.
More here.
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