The Domain Name System (DNS) in the Internet provides translation services between human readable names, such as nokia.com, that are used by underlying IP protocols in the URLs of web browsers and IP addresses. A DNS name server or resolver answers IPv4 A-record and/or IPv6 AAAA-record queries from DNS clients such as subscriber sessions. The DNS name server address can be an IPv4 or IPv6 address and must be provisioned in the client. A DNS name server reachable via an IPv4 address can also answer IPv6 AAAA-record queries and the other way around.
Similar, a NetBIOS Name Service (NBNS) provides services to register and lookup computer names on a network that uses NetBIOS as a naming service. NBNS name resolution is IPv4 only. An NBNS name server answers NBNS queries from clients such as subscriber sessions. The NBNS name server address is always an IPv4 address and must be provisioned in the client.