We now know why AWS’s DNS went kaput

On October 19, 2025, AWS suffered a DNS outage that dragged on for over a day—and after a 10-day wait, the official RCA finally spilled the beans. It turns out a hiccup in Dynamo’s DNS configuration snowballed, triggering follow-on errors in EC2 and the Network Load Balancer.

If you’re curious about the nitty-gritty, the full write-up lives on AWS’s site. Just be prepared for a deep dive into DNS, EC2 health checks, and NLB quirks!

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