The Internet Assigned Numbers Authority (IANA) is responsible for the global coordination of the DNS Root, IP addressing, and other Internet protocol resources.

http://www.iana.org/

Domain Name Services	http://www.iana.org/domains	IANA manages the DNS Root Zone (assignments of ccTLDs and gTLDs) along with other functions such as the .int and .arpa zones.
Number Resources	http://www.iana.org/numbers	IANA coordinates allocations from the global IP and AS number spaces, such as those made to Regional Internet Registries.
Protocol Registries	http://www.iana.org/protocols	IANA is the central repository for protocol name and number registries used in many Internet protocols.

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Media Types	http://www.iana.org/assignments/media-types/media-types.xhtml
Message Headers	http://www.iana.org/assignments/message-headers/message-headers.xml
Character Sets	http://www.iana.org/assignments/character-sets/character-sets.xml