Cloudflare published a technical post-mortem after a 25-minute BGP route leak that disrupted IPv6 traffic, causing congestion, packet loss, and an estimated 12Gbps throughput deficit. The incident was triggered by a deleted prefix list that made export policies overly permissive (a hybrid Type 3/Type 4 leak under RFC 7908) and was mitigated manually while Cloudflare proposed safeguards like community-based export controls and RPKI ASPA adoption. #Cloudflare #BGP
Keypoints
- A 25-minute BGP route leak from Cloudflare affected IPv6 traffic, causing congestion, packet loss, and an estimated 12Gbps throughput loss.
- The root cause was the accidental deletion of a prefix list that rendered the export policy overly permissive, advertising all iBGP IPv6 routes to external peers.
- Cloudflare characterized the event as a hybrid Type 3/Type 4 leak per RFC 7908, which propagated internal prefixes to peers in the Miami region.
- Engineers manually reverted the configuration and suspended automation, containing the impact within twenty-five minutes.
- Proposed mitigations include community-based export safeguards, CI/CD validation for policy changes, enhanced early detection, and adoption of RFC 9234 and RPKI ASPA.