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heads-up platform & cms 10 sources 1 min read

Cloudflare DNS Failures Hit .co Domains in Multi-Day Outage

What happened

Cloudflare experienced DNS resolution failures for websites using .co country code top-level domains from April 17-18, 2024. The incident began at 15:13 UTC on April 17 with sites intermittently returning DNS errors, preventing users from accessing affected websites. Cloudflare identified the root cause by 16:28 UTC and implemented a fix by 21:50 UTC, with full resolution confirmed at 02:00 UTC on April 18. This was part of a cluster of Cloudflare incidents including HTTP 5xx errors on April 15, container scheduling delays on April 14-15, and Analytics API problems on April 16.

Business impact

Companies using .co domains experienced complete site unavailability during DNS failure periods, directly impacting revenue and user access. The intermittent nature made the issue difficult to detect through standard monitoring, potentially extending downtime before teams realized the scope of the problem.

Background

The .co top-level domain is popular among startups and tech companies as an alternative to .com domains. DNS failures represent the most severe type of website outage since they prevent any user access regardless of underlying site health. This incident highlights the concentration risk when major CDN providers experience technical issues affecting specific domain categories.

What this means for your team

Implement DNS monitoring from multiple external locations to detect resolution failures quickly, especially if using alternative TLDs like .co. Configure backup DNS providers or secondary domains for critical services to maintain availability during provider-specific incidents. Test your incident response procedures for scenarios where monitoring systems may not immediately detect DNS-level failures. Review your domain strategy and consider maintaining primary domains across different TLD categories.

What to watch

Monitor whether Cloudflare provides a detailed post-mortem explaining the root cause of the .co domain-specific failure. Track if similar incidents affect other country code TLDs, which could indicate broader DNS infrastructure issues.

Sources

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