Dns_resolver_rootroot_servers are the root servers.
a_records is a list of names and bindings (A records) for the root servers.
aaaa_records is a list of names and bindings (AAAA records) for the root servers.
ips ip_proto is a list of ip addresses of the root servers.
val reserved_zones : ([ `raw ] Domain_name.t * Dns.Rr_map.b) listreserved_zones is a list of names and bindings for reserved zones specified by RFCs (private network address ranges, private domains)
val reserved : Dns_trie.treserved is a trie with all reserved_zones.