How the Domain Name System (DNS) Works

DNS (Domain Name System) maps human-readable domain names (e.g. google.com) to machine-readable physical IP addresses (e.g. 142.250.190.46). It avoids requiring users to memorize numbers.

When you enter a URL in your browser, the DNS resolution follows this routing sequence:

1. Local Cache Check: Browser and OS check their local DNS resolver caches.
2. Recurser Server: If not cached, query goes to the ISP or DNS resolver recursor (e.g. 8.8.8.8).
3. Root Server: Recursor queries the Root Nameserver, which points to the TLD nameserver.
4. TLD Server: Points to the TLD (Top-Level Domain, e.g., .com or .org) server.
5. Authoritative Nameserver: Queries the domain's Authoritative Nameserver to retrieve the exact A record.
6. Recursor caches the IP address and returns it to the client browser, which then establishes a socket connection.