What Is DNS Cache?
DNS Cache — a temporary local store of recent DNS lookups — letting devices and resolvers answer repeated name queries instantly instead of re-asking DNS servers every time.
How it works
Every resolved name (site.com → 1.2.3.4) is cached for the record's TTL duration. Your OS keeps a cache, your browser keeps one, and recursive resolvers keep large shared caches. This layering makes the web feel fast — most lookups never leave your machine.
Why it matters
Caching explains the classic "site moved but some users still reach the old server" — their caches hold the old address until TTL expires. Flushing the DNS cache (e.g. ipconfig /flushdns) is a standard troubleshooting step when DNS answers seem stale. See how DNS works.
Frequently asked questions
What does the DNS cache do?
It stores recent name-to-IP lookups locally so repeated queries answer instantly without contacting DNS servers again.
How long do DNS cache entries last?
Until the record's TTL (time-to-live) expires — set by the domain owner, commonly minutes to hours.
How do I clear the DNS cache?
On Windows: ipconfig /flushdns; macOS: dscacheutil -flushcache (with mDNSResponder restart); browsers also have internal caches cleared via their settings.
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