(Internet Assigned Numbers Authority, www.iana.org) An operating unit of the Internet Corporation for Assigned Names and Numbers (ICANN) that maintains the top-level domain, IP address and protocol number databases. The word "authority" means that IANA keeps authoritative records, but it has no jurisdiction over Internet activity and does not resolve address conflicts.

IANA coordinates all top-level domains such as .com and .org and country codes such as .us and .ca, which is necessary for the Internet's root servers and naming system (see DNS). It is also a registry for the many numerical codes assigned to data types and commands in the large variety of protocols used on the Internet, including routing and e-mail protocols, port numbers and multicast and Ethernet addresses.

IANA provides coordination of IPv4 and IPv6 addresses that the Regional Internet Registries (RIRs) around the world allocate to large companies, carriers and ISPs. It also assigns autonomous system (AS) numbers that are used by various routing protocols. See ICANN.

  RIR       Geography        URL

  AfriNIC   Africa           www.afrinic.net
  APNIC     Asia             www.apnic.net
  ARIN      North America    www.arin.net
  LACNIC    Latin America
             Caribbean Isl.  www.lacnic.net
  RIPE NCC  Europe,
             Middle East,
             Central Asia    www.ripe.net