alexa-site-nameservers: the nameservers of Alexa sites advertised by NS records
dnsrd-syslog-codes: DNS Resources Directory (DNSRD)
dns-root-servers: root zone's nameserver record data for various resource types
dnsbrute-resolvers-list: list of public-facing nameservers via dnsbrute tool
tld-whois-servers: the host names for WHOIS services listed by top-level domain
xdns-asn-netdesc: number of nameservers, autonomous system number, description