Monitoring the Registro .it Anycast DNS

The use of anycast addressing is the best solution to use in order to deploy a resilient and distributed DNS system, able to deliver low response time, and be robust to DDoS (Distributed Denial of Service) attacks. Currently the Registro .it runs DNS unicast nodes at selected locations and two different DNS anycast clouds: one has been developed by Registro .it and is fully managed by it; the other one is provided by a third party company which, at the time of this document, is named Netnod. Netnod complements the Registro .it nodes by adding many international locations on vantage points not served directly by Registro .it authoritative nameservers. In this document, the two different solutions implemented by Registro .it in order to monitor the anycast DNS nameservers are described.