Size a DNS64 resolver: synthesis rate, cache footprint and the share of queries needing AAAA synthesis.
DNS64 answers AAAA queries for IPv4-only names by synthesising a record inside the NAT64 prefix. Only the IPv4-only share needs synthesis; the rest is answered natively and can be cached normally. DNS64 sits on the critical path of every connection in an IPv6-only network, so undersizing its cache turns a name lookup into the slowest part of the request.
DNS64
synthesis rate = queries per second × share of IPv4-only destinations; cache memory = cached names × bytes per entry.
synthesis rate = queries per second × share of IPv4-only destinations; cache memory = cached names × bytes per entry. DNS64 answers AAAA queries for IPv4-only names by synthesising a record inside the NAT64 prefix. Only the IPv4-only share needs synthesis; the rest is answered natively and can be cached normally.
DNS64 sits on the critical path of every connection in an IPv6-only network, so undersizing its cache turns a name lookup into the slowest part of the request.
This calculator takes 4 inputs: DNS queries per second, Destinations that are IPv4-only, Distinct names cached, Bytes per cache entry. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.