Domain check-up
Bring DNS, the HTTPS certificate and HTTP headers into one operational view. Locate the layer needing investigation without a misleading security score.
No messages are sent and no mailboxes are tested. Queries are not stored. DNS uses Google Public DNS; HTTPS checks originate from our server.
How to interpret and act
If DNS does not return the expected IP, check the zone and cache before changing the web server. If the certificate fails, inspect its name, chain and renewal in SSL Checker. Check the HTTP status and final destination: redirects to another domain may be intentional. Use the HTTP inspector to examine each step.
Limitations
A point-in-time check from this server: not monitoring, a performance test, a security audit or a Google assessment. HTTPS checks port 443. Headers use HEAD and up to five redirects; some sites respond differently to GET. DNS and HTTPS may observe different IPs due to load balancing.
Technical sources
RFC 1034 · RFC 9110 · RFC 8446
Continue troubleshooting
DNS lookup · SSL/TLS checker · HTTP header inspector · Email diagnostics