Domain Health Checker
Combine NS, A/AAAA, MX, SOA, and SPF hints into one scored checklist.
The DNS Checkers domain health checker combines several DNS observations into a single operational snapshot: nameserver presence, web addressing (A/AAAA), mail exchangers, SOA availability, and a lightweight SPF TXT hint. The numeric score is a heuristic to prioritize fixes — not a marketing badge, not a PCI audit, and not a guarantee of global uptime. Think of it as a structured clipboard for change windows.
What “healthy” means here
A healthy zone for a typical brochure site usually has working NS delegation, at least one reachable address record, and an SOA. If you send or receive email on the domain, MX plus SPF/DKIM/DMARC become part of health in the real world. Phase 2 tools expand dedicated email authentication checks; this Phase 1 view already flags missing SPF-looking TXT data so you know where to invest next.
Scores drop more aggressively for missing NS than for missing SPF because a zone without nameservers is not resolvable at all, while missing SPF is a deliverability and policy gap that still allows many sites to “work” in a browser.
TTL and SOA notes
TTL values trade agility for cache efficiency. Low TTLs make emergency cutovers faster but increase query volume on busy zones. High TTLs stabilize popular records yet prolong bad answers after mistakes. SOA refresh, retry, expire, and minimum/negative-cache fields matter most when you run secondary nameservers. Even on managed DNS, glancing at SOA after a migration confirms you are looking at the zone you think you are.
Honest scope and next steps
Checks run from this server. CDN steering, geo-DNS, and firewalls that treat our IP differently than your users can still produce surprises. Use health as a checklist, then verify with propagation and targeted MX/TXT lookups. Educational deep-dives live on the DNS Checkers blog, including nameservers versus hosting and email authentication primers.
If you are preparing AdSense-quality content sites of your own, notice the pattern: tools that explain limitations, interlink related utilities, and avoid fake global maps tend to earn more durable trust — from users and from reviewers.
Using the score in change control
Treat the DNS Checkers score as a triage signal. A sudden drop after a registrar update usually means NS broke. A mild drop after adding a subdomain may simply reflect missing SPF on a brand-new zone you have not finished configuring. Never chase a perfect 100 if your domain is intentionally mail-less or parked — instead annotate why certain checks do not apply in your runbook.
Share health snapshots with clients by exporting the checklist items into your project wiki. Combine with propagation screenshots when you need to prove that public resolvers have caught up. For email-heavy domains, continue into SPF, DKIM, and DMARC tools once the base score stabilizes above your team’s threshold.
Frequently asked questions
Quick answers about propagation, resolvers, and how this checker works.
Are these results global? +
Results reflect what this DNS Checkers server and the public resolvers it queries currently see. Propagation can still differ elsewhere.
How often should I re-check? +
After a DNS change, re-check every few minutes while respecting TTL. Avoid hammering resolvers; our tools are rate limited.
What if records are empty? +
Empty answers can mean NXDOMAIN, no records of that type, a timeout, or a resolver that filters the query.
Is DNS Checkers free? +
Yes. Phase 1 tools are free and supported by privacy-respecting AdSense inventory once you enable it.
Where can I learn more? +
Read the DNS Checkers blog for guides on propagation, DNSSEC, email authentication, and nameserver strategy.