Simplified example of how DNS works
- Client enters a domain name (www.domain.com) into his browser.
- The browser contacts the Client's ISP for the IP address of the domain name.
- The ISP first tries to answer by itself using "cached" data.
- If the answer is found it is returned. Since the ISP isn't in charge of the DNS, and is just acting as a "dns relay", the answer is marked "non-authoritative".
- If the answer isn't found, or it's too old (past the TTL), then the ISP DNS contacts the nameservers for the domain directly for the answer.
- If the nameservers are not known, the ISP's looks for the information at the "root servers", or "registry servers". For com/net/org, these start with a.gtld-servers.net.
NOTE: The "whois" information is never used for DNS, and is often misleading and inaccurate!
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