DNS Root Server

DNS root servers are the top-level [[nameserver|nameservers]] of the [[dns|DNS]] hierarchy, responsible for answering queries about the locations of [[tld|TLD]] nameservers. There are 13 logical root server addresses (labeled A through M), each operated by a different organization and reachable at hundreds of physical locations worldwide via [[anycast|anycast]] routing. The [[iana|IANA]] Root Zone Database, maintained by ICANN, defines which nameservers are authoritative for each TLD, and root servers serve this [[root-zone|root zone]] data. When a [[recursive-dns|recursive resolver]] encounters a name it has not cached, it contacts a root server first to find the responsible TLD server.