What Is a DNS Checker?
A DNS checker queries authoritative nameservers to retrieve DNS records for any domain — including A, AAAA, MX, CNAME, TXT, NS, and SOA records. For SEO specialists, DNS health is foundational: a misconfigured record can silently break email delivery, prevent HTTPS, or split indexing signals across multiple versions of a site.
Key DNS Record Types Explained
The A record maps your domain to an IPv4 address and is the most fundamental record for web hosting. MX records direct email to the correct mail server. TXT records carry SPF, DKIM, and DMARC data that determine your email sender reputation. CNAME records create aliases, commonly used for subdomains and CDN configurations.
DNS Propagation and Its SEO Impact
When you change DNS records, the update propagates globally over 24–48 hours as caches expire. During this window, some users hit your old server while others reach the new one. Monitor crawl errors in Google Search Console during the propagation period after any DNS change.