Internet Assigned Numbers Authority (“IANA”)


IANA helps to identify standards; these standards facilitate agreement. This agreement, such as what a signal means, is required for communication to effectively function.

IANA keeps track of some various things. At least some of the things they keep track of are shown by IETF Assignments (Index of IANA Protocol Registries) and IANA Protocol Registries.


It is unfortunate that DHCPv6's “Identity Association for Non-temporary Addresses” (“IA_NA”), as noted/defined by RFC 3315 (DHCPv6)'s section 22.4 (IA_NA), has been abbreviated (by Microsoft) to IANA. Apparently Microsoft caused this confusing situation by leaving the underscore out of IA_NA. However, Win Svr 2008's terminology is different than the RFC's. The RFC's terminology (“IA_NA”) is likely to be used by some people, including people who aren't using Windows. Using the underscore is also less confusing by people who are familiar with the Internet Assigned Number Authority's abbreviation. For these reasons, the recommended abbreviation for the DHCPv6 field is “IA_NA” (including the underscore), and NOT to use IANA (without the underscore).

Organization logo

The organization is typically abbreviated as IANA, in all capital letters, although the logo shows the abbreviation lowercased.

IANA small logo, IANA large logo

[#ianaport]: Ports (TCP, UDP)

Firefox users who want to see the prettiest version, without needing to interact with multiple pages, may wish to use the XML version: IANA's service names/port numbers in XML format.

The web page of IANA port numbers redirects to a combined IANA Service Name and Transport Protocol Port Number Registry which is where IANA Service Names now also redirects. All of these locations now redirect to a format that the web server believes will be preferable. In some cases, that may end up being IANA service names port numbers in XHTML format (page 1), which seems to have data split into over 100 pages (134 pages as of September 10, 2013). Alternatively, IANA's service names/port numbers in XML format may be rendered as a single page. IANA's service names/port numbers in “Plain text” format is also available, as well as IANA's service names/port numbers in Comma Separated Values format. There may be some cross-linking: the XHTML version may have hyperlinks to the CSV and “Plain text” versions. Unfortunately, this default version does not seem to link to the giant XML version which is often the easiest to use (although it does load more slowly).

A process for getting a reservation involves visiting IANA port services. In Unix, a file named /etc/services is often pre-bundled with an operating system, and is similar to IETF assignment of port numbers which has strong similarites with (and might be identical to) IANA's list.

Even popular software can conceivably use a port that is not on IANA's list. A glaring example is CARP: this is described by: Wikipedia's article on CARP: section about not having an official Internet Protocol number.

IPv6 and IPv4 addresses
Address usage

IANA's documentation about IPv4 address space assignments, IANA's documentation about IPv6 address space assignments. Those will show that most addresses have been distributed by RIR's.

Another way to determine who is currently using an address is to check with the RIR's. e.g., the upper-right corner of ARIN WHOIS RESTful Web Service.

[#rir]: Regional Internet Registries (RIRs)
American Registry for Internet Numbers (ARIN)
Coverage area

Currently serves the United States of America (USA), some islands (Hawaii, which is a state of the USA, and some of the Caribbean islands (South of the state of Florida)), Canada, and... Antarctica. The full list is available at ARIN Region. Wikipedia's article for “American Registry for Internet Numbers”, section called “Service Region” lists some of the nations historically covered.


ARIN logo. A slightly larger version: Wikipedia's page on Arin_rtm.jpg.


Nice fact: ARIN's WHOIS-RWS (WHOIS RESTful web service) reports who an IPv4 address is assigned to. Other RIRs do this for IPv4 addresses allocated to them, but do not provide any pointers for an IPv4 that is not handled by that RIR. ARIN will point out which other RIR has the IPv4 address allocated. (IPv6 addresses haven't been tested at the time of this writing; perhaps they are treated in a similar fashion.)

Note that although the term “WHOIS” can also be used in ways related to DNS addresses (see: WHOIS lookups of DNS domains), this is looking up information about IP addresses. The software used for WHOIS lookups may also be useful for looking up information about IP addresses. Trying to use ARIN's WHOIS-RWS to look up information about a DNS name will not work, but specifying an IPv6 address or an IPv4 address ought to work out alright.

Also, ARIN's list of countries lists which RIRs are handled by which nations. Hovering a rodent over the map may highlight which nations are controlled by an RIR.

“Latin America and Caribbean Network Information Centre” (“LACNIC”)
Alternate Names

According to Wikipdia's article for “Latin America and Carribbean Network Information Centre”, there is “Registro de Direcciones de Internet para América Latina y Caribe” in Spanish, and “Registro de Endereçamento da Internet para América Latina e Caribe” in Portugese. Note that both of those have “América”, and the Portugese variation also has another character that is not a letter coming directly from the standard English alphabet.

Coverage area

LACNIC now serves Mexico and Central America (parts of North America that are South of Mexico) and the continent of South America. Also included are some of the islands in the Caribbean region, although some of the Caribbean region is still by ARIN.

LACNIC logo, LACNIC logo update announcement (translated to English), older LACNIC logo
Coverage area


Wow, that's a shocker. This one is probably the easiest to remember the territory (if the name is remembered). Africa (including the island of Madagascar) is handed by AfriNIC.

Previously, North Africa was handled by RIPE-NCC, and South Africa by ARIN, except for the island of Madagascar which was handled by APNIC (which handles other island nations).

AfriNIC Logo, AfriNIC FavIcon

Before mentioning the rest in much more detail, a brief historical note: Previously all of the territory just mentioned was all handled by ARIN, except for much of Northern Africa which was handled by RIPE-NCC, and the island of Madagascar (located near Africa which was handled by APNIC).

Asia-Pacific Network Information Centre (APNIC)
Coverage Area

APNIC has been more stable over the years: it is older than some of the newer RIRs, and compared to other older RIRs, APNIC has experienced less changes in the territory that it covers.

APNIC handles SouthEast Asia (including Afghanistan, India, China, Mongolia, Japan) and Australia and many island nations (such as New Zealand).

Historically, APNIC also handled Madagascar until AfriNIC existed.


See: APNIC Formal Logo. The right side of the page has a frame linking to a zip file.

It appears there may also be a former logo: former logo?.

Réseaux IP Européens Network Coordination Centre (“RIPE NCC” or “RIPE-NCC”)

The name RIPE is French for “European IP Networks”, although non-European nations (most notably Russia) are handled by this RIR.

Coverage area

“Réseaux IP Européens Network Coordination Centre” (“RIPE NCC”) handles the rest of the world, including Europe and much of Asia, notably including Russia, as well as Greenland (near Canada).

Prior to AfriNIC, the island of Madagascar was handled by APNIC and Southern Africa was handled by ARIN, and RIPE-NCC handled the rest of Africa (seemingly following a pattern of simply handling everything that isn't handled by any of other RIRs).

page about the RIPE NCC logo.
Multicast address assignments
IANA (IPv4) Multicast Address Assignments, IANA IPv6 Multcast Address Assignments
[#ianaptcl]: Protocols numbers specified in IP packets

IP packets then contain their protocols: For IPv4 packets, the protocol is specified in a field called “Protocol”, and in IPv6 the protocol is specified in a field called “Next Header”. These are documented by IANA protocol numbers, and at least partially documented by MS KB 289892: Protocol Numbers. On Unix systems, a file named /etc/protocols may also document some of the key protocols.

(There is a similar type of concept for frames, called EtherType. However, although IANA may document these, EtherType is primarily under the direction of IEEE. So, the topic of EtherType is documented in more detail in the section about IEEE rather than IANA.)

RFC 5237 - IANA Allocation Guidelines for the Protocol Field has been made part of IETF BCP 37.

Data for specific protocols
e.g. IANA ARP parameters, including Hardware Types, ICMP (for IPv4) parameters, ICMPv6 Parameters

Internet Message Content Types

Misc notes: IANA was once a single person, at least in practice. This can be seen with how IANA is referenced by RFC 2468: I remember IANA.

IANA may have some control over other numbers, such as any Ethernet OUI assigned to IANA. e.g.: RFC 5342: “IANA Considerations and IETF Protocol Usage for IEEE 802 Parameters”, Section 2.1.1: “EUI-48 Allocations under the IANA OUI” However, this does not mean that IANA is in charge of all OUIs. (It is simply in charge of an OUI assigned for use by IANA, similar to how other OUIs are allocated/assigned for use by other organizations.)