Domain diagnostics tools for DNS, WHOIS, and SSL troubleshooting

Run an end-to-end diagnostic workflow across DNS records, propagation visibility, WHOIS intelligence, and certificate posture. This toolkit is built for operations teams that need fast triage during outages and planned changes.

Jump directly to DNS Propagation Check, Whois Search, or SSL Checker depending on the incident domain.

What the suite includes

  • Reachability: ping, traceroute, and MTR show whether a host answers and which network hop drops or delays traffic.
  • Email: SMTP/MX server tests, SPF/DKIM/DMARC validation, DNSBL and URIBL blocklist checks, an email header analyser, and a delivery-path walk that sends no actual mail.
  • DNS integrity: DNSSEC chain verification, parent-vs-child delegation trace, and reverse DNS (PTR) lookups.
  • Web: HTTP response header inspection with every redirect hop, plus a full website health check across DNS, TLS, and HTTP.

A triage order that works

Start wide, then narrow. Run the website health check first; it names the failing layer directly. If DNS is the suspect, trace the delegation and confirm the authoritative nameservers agree with the parent zone. If the records look right but the host seems dead, ping it and let MTR show where packets stop. For mail problems, test the MX servers, then check the sending IP against blocklists, and paste a bounced message's headers into the analyser to see which hop rejected it. Fixing the first broken layer often clears every symptom above it.

Quick FAQ

When should I use the full diagnostics flow? Use it for migration windows, post-incident reviews, and recurring deliverability issues.

Do the email tests send real mail? No. The SMTP and delivery tests speak the protocol up to the point of acceptance, then disconnect without sending a message.

Why does traceroute show rows of asterisks? Many routers deprioritize or drop the probe packets while forwarding real traffic normally. Asterisks mid-path with a responsive final hop usually mean nothing is wrong.

Is this useful for non-DNS experts? Yes, outputs are structured for both quick checks and deeper technical analysis.

For the reasoning behind that order, read Why is my site down? A layer-by-layer triage playbook.