DomainName

A domain name is a human-readable address used to identify resources on the Internet. It maps to numerical IP addresses through the Domain Name System (DNS), enabling humans to access websites and services without memorizing numbers.

Domain names are hierarchical and composed of labels separated by dots. The rightmost label is the top-level domain (TLD), such as .com, .org, or a country-code TLD like .uk. The label to its left is the second-level domain, commonly the registered name. Subdomains, such as blog.example.com, are created by delegating authority within the zone.

DNS resolution translates a domain name into an IP address via a chain of servers. DNS records include A or AAAA for addresses, CNAME for aliases, MX for mail servers, NS for zone delegation, and TXT for arbitrary text data. DNSSEC provides cryptographic authentication of responses.

Domain names are allocated by registries for each TLD and sold through registrars. Policy and coordination are overseen internationally by ICANN, with national authorities involved in local regulations. Registrants may be required to provide contact information, though privacy services can obscure it in WHOIS in some cases.

Registrations are time-limited and must be renewed. Domains can be transferred between registrars. Risks include accidental expiration and domain hijacking, while disputes may be resolved through policy-based procedures and legal actions. Internationalized domain names allow Unicode characters, rendered via punycode for DNS compatibility.

In use, domain names support website navigation, branding, and email addressing, forming a foundational layer of Internet infrastructure.