How to Clear DNS Cache

DNS cache stores recently resolved domain-to-IP mappings so your computer doesn't have to query DNS servers for every request. But when DNS records change — after migrating hosting, updating MX records, or switching CDN providers — stale cache entries can send you to old servers long after the actual records have updated. This guide covers exactly how to clear DNS cache on every major platform, browser, and even your home router.

What Is DNS Cache?

DNS cache is a temporary database maintained by your operating system, browser, and router that stores the results of recent DNS lookups. When you visit example.com, your computer asks a DNS resolver "what's the IP address?" The answer gets cached so the next visit skips the lookup entirely — making page loads faster. But this speed comes at a cost: if the DNS records change, your cache still points to the old IP until it expires (based on TTL) or you manually flush it.

There are actually four layers where DNS cache can live:

1. Browser cache — Chrome, Firefox, Edge each maintain their own DNS cache (typically 1–2 minutes)
2. OS cache — macOS, Windows, and Linux each have a system-level DNS resolver cache
3. Router cache — Your home/office router often runs a DNS proxy with its own cache
4. ISP resolver cache — Your internet provider's DNS servers cache records too (you can't flush this one)

Quick Reference: All Flush Commands

macOS: Clear DNS Cache

macOS uses mDNSResponder for DNS resolution. The flush command has changed slightly across versions, but the core approach is the same.

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

sudo dscacheutil -cachedump -entries host 2>/dev/null | head -20

Windows: Clear DNS Cache

ipconfig /flushdns

ipconfig /displaydns

netsh int ip reset
netsh winsock reset

Linux: Clear DNS Cache

Linux DNS caching depends on which resolver your distribution uses. Modern distributions (Ubuntu 18.04+, Fedora 33+, Debian 12+) use systemd-resolved. Older systems may use nscd or dnsmasq.

sudo resolvectl flush-caches

sudo resolvectl statistics

sudo service nscd restart
# or
sudo systemctl restart nscd

sudo nscd -i hosts

sudo systemctl restart dnsmasq

sudo killall -USR1 dnsmasq

Browser DNS Cache

Browsers maintain their own DNS cache independent of the OS. If you've cleared the OS cache but still see old DNS results in your browser, the browser cache is the culprit. Each browser has an internal page for network debugging.

Router & Modem DNS Cache

Most home routers run a DNS proxy (often dnsmasq) that caches lookups for every device on your network. If every device on your network sees stale results, the router is the likely culprit.

How to Verify DNS Cache Is Cleared

After flushing, how do you know it actually worked? Here's a systematic verification approach:

1. Check Your DNS Records From Outside

Use our DNS Record Lookup tool to query the domain. It queries Google's public DNS (8.8.8.8), bypassing your local cache entirely. Compare what you see in the tool with what you see locally.

2. Compare With Command Line (post-flush)

dig example.com A +short

nslookup example.com

3. Use Multiple Resolvers

Query different public DNS servers to see if propagation is complete:

dig example.com @8.8.8.8 +short     # Google
dig example.com @1.1.1.1 +short     # Cloudflare
dig example.com @9.9.9.9 +short     # Quad9

If all return the same new IP, propagation is complete. If some return old values, DNS TTL hasn't expired on those resolvers yet — wait and check again.

When Should You Clear DNS Cache?

Common scenarios where flushing DNS cache solves the problem:

• After changing web hosting — Your domain points to the new server's IP, but your computer still resolves to the old one
• After updating DNS records — A, CNAME, MX changes that haven't "taken effect" on your machine
• After switching CDN providers — Cloudflare, Fastly, or Akamai changes not reflecting locally
• Getting "Server not found" errors — For sites you know are up and accessible from other networks
• DNS spoofing concerns — If you suspect DNS cache poisoning attacks (rare but serious)
• VPN disconnect issues — DNS cache can retain VPN-specific entries after disconnecting
• Local development — Switching between local/staging/production servers via hosts file and DNS

Troubleshooting: Flush Didn't Work

You ran the flush command but still see old DNS results. Here's what to check, in order:

1. Browser cache is the culprit. After flushing the OS cache, restart your browser completely (not just close tabs — quit the application). Or clear the browser's DNS cache using the internal pages shown above.
2. Your router is caching. If multiple devices on the same network see old results, power-cycle the router.
3. TTL hasn't expired on upstream resolvers. Your ISP's DNS servers and public resolvers like Google (8.8.8.8) cache records based on TTL. Check the SOA record's minimum TTL field to see how long other resolvers will cache the old value. Use our DNS Record Lookup and select "SOA" to check.
4. You're checking the wrong domain. Verify you're querying the exact domain you changed — www.example.com and example.com are separate DNS records with separate caches.
5. The DNS change hasn't propagated yet. If you just made the change, give it 5–30 minutes. Check propagation with a tool like whatsmydns.net to see results from DNS servers worldwide.

FAQ