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About DNS Checker

DNS Checker is a free, production-ready lookup website at dnschecker.sd9.in. It helps operators, developers, and mail admins inspect what public resolvers currently return for a hostname.

Hosting and edge path

The origin runs on Hostinger PHP. The hostname is routed through Cloudflare for TLS, caching of static assets, and a short path to Cloudflare DNS over HTTPS. HTML pages stay dynamic so lookup forms and canonical URLs remain accurate.

What the product does

• Live lookup for A, AAAA, CNAME, MX, NS, TXT, SOA, CAA, and PTR.
• Dedicated SPF and DMARC checkers that reuse TXT queries.
• Resolver comparison across Cloudflare, Google, and NextDNS.
• Shareable URLs with domain and type query parameters.

Accuracy notes

Public resolvers cache answers until TTL expires. A mismatch between resolvers usually means cache, not a corrupt zone. Authoritative data still lives on the nameservers listed in NS records.