Cloudflare's 1.1.1.1 DNS resolver goes dark worldwide for 62 minutes

On 14 July 2025, Cloudflare's public DNS resolver 1.1.1.1 was unavailable worldwide from 21:52 to 22:54 UTC — 62 minutes of full downtime for one of the internet's most-used public resolvers, with Gateway DNS also degraded in bursts.

The trigger was a config error, not an attack. On 6 June a change to a pre-production Data Localization Suite service had inadvertently included a reference to the 1.1.1.1 Resolver and its prefixes. It sat dormant for weeks. On 14 July a second, unrelated change to the same service triggered a global refresh of network configuration that withdrew all 1.1.1.1 Resolver prefixes from production data centres worldwide.

Cloudflare traced the underlying fault to error-prone legacy systems that hard-code explicit data-centre lists to prefixes and lack progressive, staged deployment. A coincidental BGP hijack by Tata Communications advertising 1.1.1.0/24 was spotted two minutes after the drop — exposed by the outage, not the cause of it.

Reverting the config restored traffic to about 77% of pre-incident levels, and routing was fully restored by 22:55 UTC. Cloudflare said it would deprecate the legacy prefix-mapping systems and move to staged addressing deployments with health monitoring.