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DNS resolution — how a name finds a machine
Browser cache → resolver → root → TLD → authoritative — and on the second visit, silence: a cache hit.
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THE BIG IDEA
You type firstgrade.in; the internet needs 76.76.21.21. Between those two facts sits the most heavily-cached system ever built: a detective (your recursive resolver) walking a chain of servers, each of which knows only who to ask next. Watch the full first-visit investigation, then watch the second visit ask the network absolutely nothing. Tap any block for its side of the story.
Press ▶ Play to watch it run step by step, or use the arrow buttons to go at your own pace.
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You type firstgrade.in and press Enter. Computers route by IP numbers, not names — so before ANY page can load, this name must become an address.
This lookup happens before every connection to a new domain. It is the internet’s first moving part — and usually its most invisible one.
🧑‍💻You type firstgrade.in
🗒️Browser DNS cache
handling requesthealthyjust added
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UP NEXT IN SYSTEM DESIGN
Docker vs Virtual Machines — who shares the kernel?
Two towers on one machine: every VM drags a full guest OS; every container packs only its libraries. Watch both get built.
Design a URL Shortener (bit.ly)Docker vs Virtual Machines — who shares the kernel?