We now know why the DNS failed

On October 19, 2025, AWS suffered an outage lasting over 24 hours when a misconfiguration in DynamoDB’s DNS entries broke the service’s routing control plane. That failure cascaded into EC2 API errors and left Network Load Balancers unable to route traffic, grinding large swaths of AWS to a halt.

Ten days later, AWS published the root cause analysis, confirming the sequence of DNS lookup failures in DynamoDB, subsequent EC2 service disruptions, and NLB routing issues. For the full deep dive, check out the official RCA.

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