Practical, fast, and secure online tools to help website owners, network administrators, and developers inspect, troubleshoot, and optimize domain, email, and server configurations.
Free, instant diagnostics with zero sign-up required.
Query publicly available DNS records including A, AAAA, MX, CNAME, TXT, NS, SOA, CAA, and SRV via high-speed DNS-over-HTTPS resolvers.
Inspect domain ownership, registrar accreditation, registration dates, expiration status, and authoritative nameservers for any TLD.
Resolve any IPv4 or IPv6 address back to its associated hostname using PTR reverse DNS records to verify mail server reputation.
Test domain email authentication records for SPF syntax errors and DKIM cryptographic public key validity to prevent spoofing.
Examine TLS/SSL handshake parameters, certificate chain trustworthiness, expiration countdown, and SAN host coverage.
Inspect web server response headers, follow 301/302 redirect hops, and test HSTS, CSP, and security header compliance.
Cymerit tools query public anycast resolvers securely from server endpoints, ensuring zero tracking of lookup history and instantaneous response times.
Parallel queries execute across global resolvers in under a second for maximum troubleshooting productivity.
No user queries or search histories are persistently logged or shared with third-party advertisers.
Clean, responsive interfaces optimized for desktop monitors, laptops, tablets, and smartphone screens.
No accounts, credit cards, or subscription commitments required to use any of our webmaster tools.