What Is DNS?
Understand how DNS answers name queries and why cached results can differ.
On this page
DNS, the Domain Name System, is the distributed system that answers questions about domain names. A browser may ask for the address of a website, while a mail server asks which host accepts mail. DNS provides typed records; it does not by itself host the site or deliver the email.
From a name to an answer
When you request www.example.com, a resolver looks for the relevant record, often using cached data before contacting authoritative nameservers. The authoritative servers hold the published DNS data for the zone. An A record can return an IPv4 address; an AAAA record can return an IPv6 address. The browser still has to connect to a working server afterward.
This distinction helps explain a familiar symptom: a domain can resolve correctly while its web page is down. DNS has answered its part of the question, but the web service may have failed.
Records serve different purposes
MX records direct email delivery, NS records identify authoritative nameservers, and TXT records carry text used by many verification and mail-security schemes. Each query asks for a type. A missing MX answer says nothing definitive about A records, and a working web address says nothing about mail configuration. See DNS record types for a field-by-field guide.
DNS information is arranged in zones. Delegation connects a parent zone to nameservers responsible for a child. A registrar's control panel may let you change delegation, while the DNS provider's panel edits records inside the zone.
Why two people can see different answers
Resolvers cache answers according to their TTL and may have queried at different times. Some also cache negative answers, such as a name that did not exist when it was checked. A change at the authoritative source therefore need not appear everywhere simultaneously. TTL is a cache instruction, not a promise that every device updates at one global deadline.
Use /whois to inspect the records WhoisFind currently returns, then compare with the authoritative source if you control the zone. The DNS checking guide walks through that comparison.
Sources
Try the lookup
Check a domain to see current registration and DNS signals.
Check a domain