Anycast has proven to be an effective mechanism to
enhance resilience in the DNS ecosystem and for scaling DNS
nameserver capacity, both in authoritative and the recursive
resolver infrastructure. Since its adoption for root servers,
anycast has mitigated the impact of failures and DDoS attacks
on the DNS ecosystem. In this work, we quantify the adoption
of anycast to support authoritative domain name service for toplevel and second-level domains (TLDs and SLDs). Comparing two
comprehensive anycast census datasets in 2017 and 2021, with
DNS measurements captured over the same period, reveals that
anycast adoption is increasing, driven by a few large operators.
While anycast offers compelling resilience advantage, it also shifts
some resilience risk to other aspects of the infrastructure. We
discuss these aspects, and how the pervasive use of anycast merits
a re-evaluation of how to measure DNS resilience.