What Is a Domain Name? How Domains Work on the Internet

Domains and IP Addresses: The Fundamental Relationship

Every device connected to the internet has a numerical IP address. Servers hosting websites are no exception — they have IP addresses like 172.217.16.142. But humans aren't good at remembering strings of numbers. Domain names solve this problem by providing memorable, human-readable labels for those numerical addresses.

A domain name like ipaddress.rocks is a label that, through the DNS system, maps to one or more IP addresses. When you type a domain into your browser, the DNS system resolves it to the server's IP address, which your browser uses to establish a connection.

You can think of domain names as the "street address" of a website, while IP addresses are the GPS coordinates. Both point to the same location, but one is far more human-friendly. Use our IP lookup tool to see the IP behind any domain, and our WHOIS lookup to find out who owns a domain and when it expires.

Anatomy of a Domain Name

A domain name has a specific hierarchical structure, read from right to left:

Take blog.ipaddress.rocks as an example:

• .rocks — The Top-Level Domain (TLD). This is the highest level in the domain hierarchy. TLDs include generic ones like .com, .org, .net, and hundreds of newer options like .rocks, .io, .app. Country-code TLDs (ccTLDs) like .uk, .de, .jp represent countries.
• ipaddress — The Second-Level Domain (SLD). This is the part you register. It's the unique identifier within the TLD namespace. Together with the TLD, it forms the registered domain: ipaddress.rocks.
• blog — A subdomain. Subdomains are prefixes added to registered domains. They're configured in DNS by the domain owner and can point to different servers. Common subdomains include www, mail, api, app.

The full domain system is managed by ICANN (Internet Corporation for Assigned Names and Numbers), which delegates management of TLDs to registry operators. Individual domain registrations are handled by ICANN-accredited registrars.

How Domain Registration Works

Domain registration is the process of reserving a domain name for exclusive use. Here's how the ecosystem works:

Registries are the organizations that manage specific TLDs. Verisign manages .com and .net. Public Interest Registry manages .org. Each registry maintains the authoritative database of registrations for its TLD.

Registrars are companies accredited by ICANN to sell domain registrations directly to the public. Examples include Namecheap, GoDaddy, Google Domains (now Squarespace), and Porkbun. Registrars interface with registries on your behalf.

When you register a domain:

1. You choose an available domain name and TLD.
2. You register it for 1–10 years through a registrar.
3. Your contact information is recorded in the WHOIS database.
4. You configure name servers to point to your DNS provider.
5. You set up DNS records to direct traffic to your server.

Registrations must be renewed before they expire or the domain becomes available for others to register. Check any domain's registration status, expiry date, and registrar with our WHOIS lookup.

TLDs, ccTLDs, and New Generic TLDs

The TLD landscape has expanded dramatically. Originally there were just a handful of generic TLDs (gTLDs) — .com, .org, .net, .edu, .gov, .mil. ICANN's New gTLD Program, launched in 2012, has since added over 1,500 new TLDs.

Today you can register domains with TLDs like:

• Industry-specific: .tech, .shop, .blog, .app, .dev, .io
• Geographic: .london, .nyc, .berlin
• Brand: .google, .amazon, .apple
• Fun: .rocks, .pizza, .ninja, .lol

Country-code TLDs (ccTLDs) like .uk, .de, .ca, .au are managed by each country's designated organization and often have local presence requirements. Some ccTLDs have become popular internationally for their letter combinations — .io (British Indian Ocean Territory) is widely used by tech startups, and .tv (Tuvalu) is used by streaming services.

Despite the proliferation of new TLDs, .com remains the most trusted and valuable TLD for commercial use. Users instinctively type .com and search engines have historically given slight ranking advantages to established TLDs.

Domain Privacy, WHOIS, and RDAP

When you register a domain, your contact information — name, address, phone number, email — is recorded in the WHOIS database. This database was historically public, meaning anyone could look up domain owner details. This led to spam, harassment, and privacy violations.

Today, two protections help:

WHOIS Privacy / Domain Privacy Protection: Most registrars offer free or low-cost privacy protection that replaces your personal contact info in WHOIS with the registrar's proxy details. If anyone contacts the privacy proxy, they can forward legitimate communications to you.

GDPR Impact: Since 2018, GDPR has required registrars to redact personal data from publicly visible WHOIS records for EU registrants. This has significantly reduced the amount of personal data visible in WHOIS queries globally, as most registrars applied the policy broadly.

RDAP (Registration Data Access Protocol): RDAP is the modern successor to WHOIS, providing structured, authenticated access to registration data. It's more machine-readable and supports access controls that allow different levels of data depending on the requester's credentials.

You can check any domain's registration details, name servers, and creation/expiry dates using our WHOIS lookup tool.

Frequently Asked Questions