We now know why the DNS failed

AWS’s October 19, 2025 outage that crippled DNS for over a day has finally been explained in their official root-cause analysis. It boils down to a cascading failure: a mishap in DynamoDB’s DNS configuration kicked off errors in EC2, which in turn disrupted Network Load Balancers—ultimately taking DNS offline across the board.

If you’re hungry for the full deep dive, AWS posted the detailed write-up here: https://aws.amazon.com/message/101925/ And hey, while you’re in troubleshooting mode, check out Hussein Nasser’s lineup of free and paid courses on everything from OS and networking fundamentals to backend and database engineering!

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