Wildcard DNS Checker
Detect whether a zone answers every subdomain with the same address — a wildcard (*) record. We resolve three random, never-registered subdomains and compare the answers.
About the Wildcard DNS Checker
The Wildcard DNS Checker detects whether a zone has a wildcard record (`*.example.com`) by resolving three randomly-generated subdomains that could not possibly be registered by hand, then comparing the answers. If every random subdomain returns the same address or CNAME, the zone has a wildcard rule that catches every request.
Wildcards are legitimate — SaaS platforms, hosting providers and CDNs use them to route customer subdomains to a shared front door. But wildcards can also mask misconfiguration: a subdomain finder or SEO crawler may see thousands of 'live' subdomains that all point at the same 404 page. Security-wise, wildcard MX or wildcard A can turn typos into successful phishing landings.
Use Wildcard Checker before running our Subdomain Finder (to reason about the results correctly), when auditing a newly acquired domain, or when debugging a mysterious subdomain that resolves 'by accident'. Combine with the Propagation Checker to see how the wildcard replicates worldwide.
How to use this tool
- 1Enter the required value in the input field above (domain, IP, URL, or text depending on the tool).
- 2Click the action button to run the check — results are computed instantly from our edge network.
- 3Review the parsed output, key fields and any warnings shown in the result card.
- 4Copy the result, share the page URL, or jump to a related tool from the sidebar to continue debugging.
Key features
- Three random probe subdomains — guaranteed unregistered
- Compares A, AAAA and CNAME answers for consistency
- Shows the wildcard target when one is detected
- Fast, zero setup, over DoH