What is DNS?
DNS is the naming system of the internet. It lets people use names like whenip.com instead of remembering numeric IP addresses.
- How names resolve to IP addresses.
- What a recursive resolver does.
- Why record types matter for different services.
Name to address
When you enter a hostname, your system asks a resolver for an answer.
That resolver walks the DNS hierarchy or uses cached answers to return records such as A or AAAA.
Record types
A points to IPv4.
AAAA points to IPv6.
MX is used for mail routing.
TXT often carries policy and verification data.
Why DNS breaks
Typos, stale caches, bad delegation, missing records, DNSSEC issues, and resolver outages can all cause failures.
Dual-stack behavior can also vary depending on whether a host publishes A, AAAA, or both.
Why WhenIP includes DNS tools
A quick DNS lookup helps verify whether a name resolves the way you expect.
Combining DNS with ping or traceroute helps separate naming problems from path problems.
Why does one network resolve a name differently?
Different resolvers, split-horizon DNS, and cached results can change what you see.
What is the difference between DNS and WHOIS?
DNS answers technical routing questions. WHOIS is about registration or registrar information.
Last updated: March 29, 2026