IANA — the Internet Assigned Numbers Authority — is the function, operated by ICANN, that performs the internet’s most fundamental technical bookkeeping. It manages the DNS root zone (the master list of all top-level domains), allocates large blocks of IP addresses to regional registries, and maintains the protocol-parameter registries that internet standards depend on. In short, IANA keeps the internet’s core registries authoritative and consistent.
If ICANN is the policy-making organization, IANA is the operational hand that records and publishes the results. It is quiet, technical work — but every domain lookup on Earth ultimately trusts the registries IANA maintains.
What does IANA do?
IANA’s work is to be the authoritative source for three sets of internet numbers and names. It does not make the policy for these (that happens through ICANN’s and the technical community’s processes); it carries out the careful, accurate maintenance once decisions are made. Reliability and precision are everything: an error in these registries would ripple across the whole internet.
The Internet Assigned Numbers Authority — a function operated by ICANN that coordinates the DNS root zone, IP address allocation, and protocol-parameter registries, serving as the internet’s authoritative registry keeper.
What is the root zone, and why does IANA manage it?
The root zone is the master file at the very top of the DNS. It lists every top-level domain — .com, .org, .uk, and all the rest — and points each one to the registry that operates it. When ICANN approves a new TLD, IANA delegates it by adding the appropriate record to the root, so that DNS servers worldwide know where to send queries for that extension.
Because every DNS lookup begins, conceptually, at the root, this single file is the linchpin of the entire naming system. IANA’s maintenance of it — through the publicly viewable Root Zone Database — is what keeps .com meaning the same thing everywhere. Our guide on how the DNS hierarchy works shows where the root sits.
IANA’s three core roles
| Area | What IANA does | Example |
|---|---|---|
| Domain names | Manages the DNS root zone and delegates TLDs | Adding a new gTLD to the root |
| Number resources | Allocates large IP address blocks to Regional Internet Registries | Handing IPv4/IPv6 blocks to RIRs |
| Protocol parameters | Maintains registries of values used by internet standards | Port numbers, protocol codes |
Allocation cascades downward
IANA does not give individual IP addresses to people. It allocates large blocks to the five Regional Internet Registries (such as ARIN and RIPE NCC), which in turn distribute smaller ranges to internet providers and organizations. IANA sits at the top of that distribution chain.
IANA vs ICANN
The relationship is simple once stated plainly: IANA is a function performed by ICANN. ICANN is the organization that develops policy and coordination; IANA is the operational role that records and publishes the authoritative registries. The name “IANA” predates ICANN by years — it dates to the internet’s early administration — but today the IANA functions are carried out under ICANN’s stewardship. Since the 2016 stewardship transition, that work is overseen by the global community rather than a national government.
Why does IANA matter to you?
You will rarely interact with IANA directly, but its work underpins everything you do with domains:
- Your TLD exists in the root because IANA delegated it — without that record, no one could resolve your domain.
- The Root Zone Database is the authoritative place to confirm which registry runs an extension and who its administrative contacts are.
- The whole DNS hierarchy — from root to TLD to your name — rests on the accuracy IANA maintains.
How did IANA come to be?
The name predates much of the modern internet. In the early decades of networking, the painstaking work of recording who had which numbers and names was associated with a small group of researchers, most famously the late Jon Postel, who for years effectively kept these registries by hand. As that informal stewardship became too important and too large to rest on individuals, the IANA functions were formalised and, with the creation of ICANN in 1998, carried out under that organisation’s umbrella.
A further milestone came in 2016, when oversight of the IANA functions transitioned from a contract with the US government to the global multistakeholder community. The practical effect was to make the world’s most fundamental internet registries answerable to the broad community of stakeholders rather than any single nation — a deliberate step to keep the system globally legitimate. The day-to-day work, though, is unchanged: maintain the root accurately, allocate numbers cleanly, and keep the protocol registries authoritative.
★ Key takeaways
- IANA is the function, run by ICANN, that maintains the internet’s core registries.
- It manages the DNS root zone and delegates every top-level domain.
- It allocates large IP address blocks to Regional Internet Registries and keeps protocol registries.
- ICANN sets policy; IANA performs the authoritative technical operations.
Frequently asked questions
What is IANA in simple terms?
IANA is the function that maintains the internet’s core registries: the DNS root zone of all TLDs, IP address allocation to regional registries, and protocol-parameter registries. It is operated by ICANN.
What does IANA stand for?
IANA stands for the Internet Assigned Numbers Authority. The name dates to the internet’s early administration; the functions are now carried out under ICANN’s stewardship.
What is the difference between IANA and ICANN?
IANA is a function performed by ICANN. ICANN develops policy and coordination; IANA records and publishes the authoritative registries like the root zone.
What is the DNS root zone?
The root zone is the master file at the top of the DNS, listing every TLD and pointing each to its registry. IANA manages it and delegates new TLDs. See how the DNS hierarchy works.
Does IANA give out IP addresses?
Not to individuals. IANA allocates large blocks to the five Regional Internet Registries, which distribute smaller ranges to providers. IANA sits at the top of that chain.
Where can I see IANA's list of TLDs?
IANA publishes the Root Zone Database, the authoritative public list of all TLDs and the registry operating each one.