Cloudflare 1.1.1.1 Incident on July 14, 2025
Jul 15, 2025Ash Pallarito, Joe Abley
Summary
This post details a 62-minute outage of the 1.1.1.1 DNS Resolver service caused by a misconfiguration in service topology management. A configuration error on June 6 inadvertently linked the 1.1.1.1 Resolver service prefixes to a pre-production DLS service. A subsequent change on July 14 to this DLS service triggered a global refresh of network configuration, causing the 1.1.1.1 Resolver prefixes to be withdrawn from production data centers. The incident highlights the risks of legacy configuration systems and the importance of staged deployments and comprehensive health monitoring.
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