How the domain name system really works

Every website address, every email, every app quietly relies on one of the internet's oldest and most elegant systems. This is the whole thing explained end to end — what a domain is, how a name becomes a computer somewhere in the world, and the global web of organizations that keeps it running — in plain language, and accurately.

1 · What a domain name actually is

Computers on the internet find each other by number — an IP address like 93.184.216.34. Numbers are hard for people, so we use domain names instead. A domain name is just a human-friendly label that the system translates into an address.

Names are read right to left, from the most general to the most specific. Each dot-separated piece is a label:

The full string (with that trailing root dot) is a fully-qualified domain name. When you “buy a domain”, what you're really doing is registering a second-level domain under a TLD — e.g. example under .com — which gives you the exclusive right to use it and to create any subdomains beneath it.

2 · DNS: turning names into numbers

The Domain Name System (DNS) is the global, distributed directory that maps names to addresses. Think of it as a phone book that no single computer holds — it's split across millions of servers, arranged as a tree that mirrors the dots in a name. Crucially, no one server knows everything; each level only knows how to point you to the next level down.

Here's what happens, in about a tenth of a second, the first time your device looks up example.com:

That caching is why the second visit is instant: every answer carries a TTL (time-to-live) telling resolvers how long they may remember it. DNS also stores more than addresses — A/AAAA records (IPv4/IPv6 addresses), MX (mail servers), NS (which servers are authoritative), TXT (arbitrary text, used for verification and email security), and more.

3 · The root and the root servers

At the very top sits the root zone — a relatively small, extremely important file that lists every TLD and which servers are authoritative for it. It's the master index of the internet's namespace.

The root is served by the root name servers, known by the letters A through M (a.root-servers.net … m.root-servers.net), operated by 12 independent organizations. That sounds like only 13 machines, but each letter is actually hundreds of physical servers spread worldwide using anycast — many machines answering on the same address, so you always reach a nearby one. This is what makes the root fast and nearly impossible to knock offline.

The content of the root zone — which TLD exists and who runs it — is managed through the IANA functions (see below), not by the root-server operators, who simply publish what they're given.

4 · TLDs and their types

A top-level domain is the last label of a name — the top branch of the DNS tree. There are a bit over 1,500 of them, in a few families:

World Domain Stats follows the two that carry essentially all real-world registrations: gTLDs and ccTLDs.

5 · gTLDs in depth

The original “legacy” gTLDs date from the 1980s: .com, .net, .org, plus the restricted .gov, .edu, .mil. .com alone holds well over 150 million names — more than every other gTLD combined.

For decades the list barely grew. Then in 2012 ICANN opened the New gTLD Program: any qualified organization could apply (for a US$185,000 evaluation fee) to run a brand-new TLD. Over 1,900 applications came in, and from 2013–2014 hundreds were delegated — .xyz, .top, .shop, .online, niche endings like .beer, and hundreds of brand TLDs. It transformed the right-hand side of the dot from a handful of choices into a marketplace. A further application round is planned for the coming years.

6 · ccTLDs in depth

Every country and territory with a two-letter ISO 3166-1 code gets a matching ccTLD: .de for Germany, .fr for France, .jp for Japan, .cn for China. Each is run by a national registry — often a non-profit or government-linked body (DENIC for .de, Nominet for .uk, SIDN for .nl, CNNIC for .cn) — which sets its own rules.

Those rules vary widely. Some ccTLDs are open to anyone worldwide; others are restricted to local residents or businesses. And several have been repurposed far from their country because their letters spell something useful: .io (British Indian Ocean Territory) for tech, .ai (Anguilla) for AI, .tv (Tuvalu) for video, .co (Colombia) as a .com alternative, .me (Montenegro) for personal sites. For small territories these have become significant revenue.

Because ccTLDs are run independently, they are not under ICANN's contractual reporting regime — which is why consistent numbers for them are harder to gather, and why World Domain Stats pulls each one from its own registry's published statistics.

7 · Who's who: the players

The domain industry is a layered supply chain. From the top:

Registrars and registries talk to each other over a standard protocol called EPP (Extensible Provisioning Protocol): check availability, create, renew, transfer, delete. Public lookup of who-holds-what used to run over WHOIS and is moving to its structured successor, RDAP — though since the EU's GDPR took effect in 2018, most personal contact details are now redacted.

8 · How you actually get a domain

When you register example.com at a registrar, in the background: the registrar checks availability with the registry over EPP, creates the registration, and the registry adds your name to the .com zone so DNS can resolve it. You then point the domain at your name servers.

Three parties are usually paid:

1. the registry takes a wholesale fee per year (for .com, on the order of ~US$10);
2. ICANN takes a small per-transaction fee (US$0.18 per gTLD registration/renewal/transfer as of writing);
3. the registrar adds its retail margin — and this is where promotions, privacy add-ons and renewals-at-higher-prices live.

You never “own” a domain outright; you hold an exclusive, renewable right to use it for a period (1–10 years). Keep renewing and it's effectively yours; stop, and it goes back into circulation.

9 · The life of a domain

Every gTLD registration moves through a well-defined lifecycle — the reason a lapsed domain doesn't become available the instant it expires:

10 · Zone files & counting domains

How do you count how many domains exist? Two different numbers matter:

• Registered domains — every name a registry has on its books, whether or not it currently works. This is the figure registries report and the one World Domain Stats tracks.
• DNS-active domains — names actually present in the zone file (the published list of what resolves). Always a few percent lower, because some registered names are parked, held or not yet delegated.

ICANN's CZDS (Centralized Zone Data Service) lets approved parties download gTLD zone files; that's the source of the DNS-active counts here. The registered totals come from each registry's own filings — ICANN's monthly registry reports for gTLDs, and national registries' statistics for ccTLDs. On this site, every number links back to the exact file it came from.

11 · A short history

Before DNS (to 1983). Early ARPANET computers shared a single file, HOSTS.TXT, listing every machine by name and address. As the network grew, one hand-maintained file became unworkable.

1983 — DNS is invented. Paul Mockapetris designed the Domain Name System (RFCs 882/883, later refined as 1034/1035), replacing the flat file with the distributed, hierarchical tree we still use.

1984–85 — the first TLDs. The original set arrived: .arpa, then .com, .edu, .gov, .mil, .net, .org. The first-ever .com, symbolics.com, was registered on 15 March 1985. For years the naming and numbering functions were run largely by one person, Jon Postel, as IANA.

1990s — commercialization. The US government contracted Network Solutions to run registrations; from 1995 it charged for .com names and, as the web boomed, held a hugely profitable monopoly.

1998 — ICANN is created to internationalize and depoliticize governance of the namespace.

1999 — competition arrives. The Shared Registry System split the roles of registry (wholesale) and registrar (retail), letting many accredited registrars compete to sell the same TLDs. Prices fell sharply.

2000 & 2004 — first new gTLDs (.info, .biz, .name, later .mobi, .travel, …) tested cautious expansion.

2009–10 — internationalized domains. The first non-Latin-script TLDs went live, opening the system to the world's writing systems.

2012 — the big bang. The New gTLD Program opened the floodgates; from 2013–14 the number of TLDs grew roughly tenfold.

2016 — the IANA transition. Stewardship of the IANA functions passed from the US government to the global multi-stakeholder community (via PTI).

2018 — GDPR reshapes WHOIS. EU privacy law forced the redaction of personal data from public WHOIS, accelerating the move to RDAP with tiered access.

The system that started as one text file now underpins hundreds of millions of names — and keeps growing.

12 · Glossary

Written for World Domain Stats. For the live numbers behind all of this, see every tracked TLD, the registrar landscape, or the free API & MCP server.