How a DNS lookup works
- You type a domain into your browser.
- Your device asks a DNS resolver, usually run by your internet provider or a service such as Cloudflare or Google.
- If the resolver doesn’t have the answer cached, it asks the root servers, then the servers for the top-level domain (such as .com), then the domain’s own name servers.
- The IP address comes back, and the browser connects to the website’s server.
This usually takes milliseconds, and answers are cached for a set time, called the TTL (time to live).
Common DNS records
- A and AAAA: point a domain to an IPv4 or IPv6 address.
- CNAME: points one name to another, such as www to the main domain.
- MX: says where the domain’s email should be delivered.
- TXT: holds text such as SPF, DKIM and DMARC records for email, and verification codes for tools like Google Search Console.
- NS: names the servers responsible for the domain.
DNS and SEO
DNS doesn’t affect rankings directly, but slow or failing DNS makes a site slow or unreachable, for visitors and for Googlebot. Use a reliable DNS provider, keep records tidy when you change hosts, and lower the TTL before a migration so the changes take effect quickly.