Cloudflare introduces the Advanced DNS Protection system to defend against sophisticated DNS-based DDoS attacks. This system is in beta and free for Magic Transit customers. DNS attacks can disrupt websites by overwhelming DNS servers. The blog post explains the challenges of mitigating sophisticated DNS attacks and introduces the Advanced DNS Protection system's features and customization options. Cloudflare's global network and data processing capabilities are leveraged to protect customers. The system uses a data model to distinguish between legitimate and malicious DNS queries, dropping the latter. Technical challenges in designing the system include data processing, compact representation of query data, data distribution, and built-in tolerance. Cloudflare invites non-customers to inquire about protecting their DNS servers and existing customers to enable the new system.