How to Flush DNS Cache on Mac, Windows & Linux
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Clear your DNS cache in one command (macOS, every Windows version, and Linux distros) plus how to flush browser DNS and confirm it worked.
The Domain Name System (DNS) translates human-readable domain names into the IP addresses computers actually connect to. To speed things up, your operating system caches those lookups locally, but a stale cache can serve outdated records, which is exactly the problem when you've just changed an MX, TXT, or CNAME record and the old value keeps resolving. Flushing the DNS cache forces your system to fetch fresh data. This guide covers how to do it on Windows, macOS, and Linux, and how to confirm it worked.
What the flush DNS command does
The flush command tells your operating system to discard its cached DNS entries, so the next lookup for any domain retrieves current data from your DNS servers. It's the fastest fix when a record change hasn't taken effect locally, when a site resolves to the wrong address, or when you're troubleshooting connectivity that points at DNS.
Each OS has its own flush command; Linux commands vary by distribution.
Each operating system has its own command, so let's walk through Windows, macOS, and Linux in turn.
Flushing DNS cache on Windows
- Open Command Prompt as an administrator. Press the Windows key, type "Command Prompt," right-click it, and choose "Run as administrator."
- Run the flush command. Type
ipconfig /flushdnsand press Enter. Windows clears its resolver cache. - Confirm it worked. You should see the message "Successfully flushed the DNS Resolver Cache."
ipconfig /displaydns.
Flushing DNS cache on macOS
- Open Terminal. Go to Applications → Utilities and launch Terminal.
- Run the flush command. Type
sudo killall -HUP mDNSResponderand press Enter. This signalsmDNSResponder, the process responsible for DNS caching, to clear its cache. - Enter your password. You'll be prompted for your administrator password; it won't display as you type. Press Enter.
Flushing DNS cache on Linux
Linux distributions handle DNS caching differently, so the command depends on which resolver your system runs.
- Open a terminal. Use a shortcut like Ctrl+Alt+T or search for "Terminal" in your application launcher.
- Run the command for your resolver:
sudo systemd-resolve --flush-caches (or sudo resolvectl flush-caches on newer releases).
- NetworkManager: sudo systemctl restart NetworkManager.
- dnsmasq: sudo systemctl restart dnsmasq.
If you're unsure which resolver you use, systemd-resolved is the default on most modern distributions. Consult your distribution's documentation for anything unusual.
Flushing your browser's DNS cache
Browsers keep their own DNS cache that survives an OS-level flush. In Chrome, visit chrome://net-internals/#dns and click "Clear host cache"; in Firefox, DNS is cached briefly and clears on restart. If a site still resolves incorrectly after an OS flush, clear the browser cache too.
When flushing isn't enough
While flushing the cache resolves many issues, some DNS problems need a closer look.
Work through these when a cache flush alone doesn't fix DNS resolution.
- DNS errors and misconfigurations: Double-check your records with the DNS lookup tool to confirm the published values are what you intended.
- DNS cache poisoning and spoofing: Keep your DNS software current and use protective measures against cache poisoning.
- Network connectivity and server availability: Confirm your connection is stable and your DNS servers are reachable.
- Firewall and security settings: Make sure a firewall or security tool isn't blocking DNS requests on port 53.
Common issues when flushing DNS
The flush command runs but the old record still resolves.
The record's TTL controls how long resolvers upstream of you keep the old value; your local flush can't clear their caches. It can also be your browser's separate cache. Wait for the TTL to expire, flush the browser cache, and confirm with the DNS lookup tool rather than the browser.
"The requested operation requires elevation" on Windows.
ipconfig /flushdns needs administrator rights. Close the window and reopen Command Prompt with "Run as administrator" before running the command again.
macOS shows no confirmation message.
That's expected, killall -HUP mDNSResponder prints nothing on success. If you got no error, the flush worked. Test by resolving a domain that recently changed.
The Linux command isn't found or has no effect.
You're likely targeting the wrong resolver. Check whether systemd-resolved, NetworkManager, or dnsmasq is running with systemctl status, then use the matching command from the list above.
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Written by
Samuel ChenardCEO & Co-Founder, Palisade
Samuel Chenard is the CEO and co-founder of Palisade, AI-first DMARC software for IT teams and MSPs, from one domain to thousands.
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