What each record does
- A and AAAA point a hostname at an IPv4 or IPv6 address. These are what browsers connect to.
- CNAME makes one hostname an alias of another, common for
wwwand for services like Shopify, Vercel or a CDN. A name with a CNAME cannot have other records. - MX lists the mail servers that accept email for the domain, lowest priority number first.
- NS names the nameservers that are authoritative for the domain, which is where every other record is managed.
- TXT holds free-form text: SPF, domain verification for Google Search Console and other services, DKIM and DMARC (on their own subdomains).
- SOA is the zone's start of authority: the primary nameserver, admin contact and timers.
- CAA says which certificate authorities may issue certificates for the domain. If it is set and your CA is not listed, renewals fail.
Why DNS matters for SEO
Search engines cannot crawl a site they cannot resolve. A wrong A record after a host move, a missing www record, or a lapsed nameserver takes the whole site offline. DNS is also where you prove ownership in Google Search Console with a TXT record.
Checking a DNS change
Every record has a TTL, the number of seconds resolvers may cache it. After you change a record, old answers can linger for up to that long. Lower the TTL a day before a planned move, then raise it again afterwards.
This lookup asks Cloudflare's public resolver, so it reflects what most of the internet sees, not your local cache. For email records specifically, the email auth checker reads SPF, DKIM and DMARC and tells you what is wrong. For registrar and expiry details, use the WHOIS lookup.