How the resolver cache works
The DnsClient service stores recent answers — mainly A and AAAA records mapping names to IPv4 and IPv6 addresses — along with a TTL, the expiry time the domain itself sets. Until the TTL runs out, any app that asks about that name gets the cached answer instantly; after that, Windows queries the configured resolver again, which is usually your router, your ISP, or a public one like 1.1.1.1. The cache also remembers failures: a temporary DNS error can be stored as a negative entry, which is why a site that briefly failed can stay "broken" for minutes after it recovered.
Two layers sit on top of this system cache. Browsers keep their own small DNS cache, and if DNS-over-HTTPS is enabled the browser resolves names itself, bypassing Windows entirely. So depending on the setup, the cache that matters for a specific site may not even be the one ipconfig talks to.
When flushing actually fixes something
Flushing is a correctness repair, not a speed trick — it earns its keep in a short list of concrete situations:
- You edited the hosts file and Windows keeps serving the old answer until the TTL expires
- A site moved to new IP addresses and your machine keeps dialing the dead ones
- You switched between a VPN and the regular network and cached private-zone names no longer resolve
- A transient failure got stored as a negative entry and the site stays unreachable though it is back
- You changed the DNS server (or its filtering rules) and want answers from the new one immediately
How to inspect and flush it
Open Terminal or PowerShell and run ipconfig /displaydns to see the cached entries with their TTLs — it is the fastest way to confirm a stale record before blaming your network. Running ipconfig /flushdns empties the cache in under a second and prints a confirmation; no reboot, no service restart needed. In the browser, clear its layer separately: in Chrome-based browsers, chrome://net-internals/#dns has a Clear host cache button, and Firefox re-resolves on restart.
If lookups misbehave system-wide even after a flush, restart the DnsClient service in services.msc and check which resolver Windows is actually using on the adapter's DNS assignment page. Restarting the service also drops its cache, so it works as the deeper version of the flush. And if you found this article hoping flushing would make browsing faster: it will not — that myth deserves its own autopsy.
Questions and Answers
How do I flush the DNS cache in Windows 11?
Open Terminal or PowerShell and run ipconfig /flushdns — it takes under a second and needs no reboot. Browsers keep a separate DNS cache, so clear that one too if the problem lives in a single browser.
Where is the DNS cache stored on my PC?
In RAM, inside the DnsClient service — there is no file on disk to delete. You can view the current entries with ipconfig /displaydns or clear them with ipconfig /flushdns.
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