DNS & Domain
Open DNS Lookup →Match the record to the question
A records describe IPv4 addresses and AAAA records describe IPv6 addresses. CNAME points one DNS name to another name. MX identifies mail-exchange hosts, NS identifies name servers, and TXT carries text used by many different services. Start with the exact hostname involved in the fault: the domain apex, www name and mail hostname need not share records.
Use the lookup to establish facts
Enter a domain in DNS Lookup and select one supported record type. Record the query name, type and returned values before changing DNS. A website investigation usually starts with A and AAAA; email routing starts with MX, then address lookups for its mail hosts. Use Email DNS Health when you also need authentication-policy context. A TXT answer by itself is not an assessment of SPF or DMARC correctness.
Understand an empty answer and a failed lookup
No answer for a type does not necessarily mean the name is absent. A name can have A records without AAAA, while a DNS failure can reflect resolver or authoritative-server problems. Preserve the actual response rather than translating every failure into “domain not found.” Check NS information and compare resolvers when the result is unexpected. DNS lookup success does not establish that the target port or application is reachable.
Verify changes without assuming instant propagation
Recursive resolvers cache answers and can temporarily disagree during a change. Compare the same name and type through DNS Resolver Comparison, and check the intended authoritative configuration. A TTL is a caching instruction, not a global completion countdown. After the address answers match your plan, test HTTPS and certificates on the hostname people actually use.
Worked example
Illustrative example — not a live test www.example.com A → 192.0.2.20 www.example.com AAAA → no answer Interpretation: this example publishes IPv4, not an IPv6 address. Documentation addresses above are not public test targets.
What to check next
- Identify the exact hostname and record type.
- Compare resolvers if answers differ from the intended configuration.
- Run the relevant web or email checks after DNS is correct.
Common questions
Should I enter a complete website URL?
Use the domain or hostname for DNS Lookup. DNS records belong to names, not URL paths.
Does an A record mean HTTPS will work?
No. It supplies an address. Network reachability, TLS and HTTP must still be tested.