Domain names are organized and managed by a system called the Domain Name System (DNS), which is a hierarchical, decentralized system for managing the mapping of domain names to IP addresses. The DNS is made up of several different components, including:
Top-level domains (TLDs): TLDs are the highest level of the domain name hierarchy and include domain extensions like .com, .org, .edu, and .gov.
Registrars: Registrars are organizations that are authorized by ICANN (Internet Corporation for Assigned Names and Numbers) to register and sell domain names.
Registries: Registries are organizations that operate and maintain the databases of domain names for specific TLDs.
Authoritative DNS servers: These servers are responsible for providing the IP addresses associated with specific domain names.
DNS resolvers: These are servers that receive domain name requests from users and return the associated IP addresses.
When a user wants to register a domain name, they can do so through a registrar. The registrar will check with the registry to see if the domain name is available, and if it is, the registrar will register the domain name on behalf of the user. The registry will then update its database with the new domain name and the IP address of the authoritative DNS server for that domain name.
When a user types a domain name into their browser, the browser sends a request to a DNS resolver for the IP address associated with the domain name. The DNS resolver will then check its cache for the IP address, and if it doesn't have it, it will query the TLD's DNS server, which will then query the authoritative DNS server and get the IP address associated with the domain name and return it to the browser.
ICANN is responsible for managing the overall system of domain names, including approving new TLDs, accrediting registrars, and enforcing policies related to domain name registration and use.
