Part of this problem is authoritative dns server operators not sharding their zones. The only provider I know who does this correctly is AWS Route 53. Your zon

Part of this problem is authoritative dns server operators not sharding their zones. The only provider I know who does this correctly is AWS Route 53. Your zone gets assigned 4 unique authoritative servers from a set of namespaced shards. eg ns-2048.awsdns-64.com Someone else can create a zone for the same domain but will map to different shard so no real world effect. Always surprising to me that hardly any providers do it.