Wildcard DNS records answer for names that do not have explicit records. They are useful, but they can hide missing subdomain configuration.
Useful dig commands
dig random-test-name.example.com A
dig app.example.com ATroubleshooting checklist
- Test a random hostname that should not exist.
- Test the intended hostname.
- Check whether a specific record overrides the wildcard.
- Do not use wildcard DNS as a substitute for proper application routing.
How to interpret the result
If the answer matches the expected value, DNS is probably not the layer causing the current symptom. Continue with HTTP, TLS, mail server, firewall, or application checks. If the answer is missing, stale, or different between resolvers, keep the investigation in DNS until the public answer is correct.
Support note
When opening a ticket with a DNS provider, include the exact name, record type, resolver tested, returned value, and time of the lookup. That is much more useful than saying “DNS is not working.”