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Flush DNS on Linux: systemd-resolved & more (2026)

Flush the DNS cache on Linux with resolvectl flush-caches (systemd-resolved), plus nscd, dnsmasq and BIND. Commands by setup, with verification steps.

S

Sleezr Team

·2 min read
Flush DNS on Linux: systemd-resolved & more (2026)

Table of Contents

Need to flush the DNS cache on Linux? On modern distributions using systemd-resolved, run:

BASH
sudo resolvectl flush-caches

Use it after editing /etc/hosts, changing resolvers, or testing a migration when a hostname still resolves to an old IP.

How to flush DNS on Linux

To flush DNS on Linux, run the command for your resolver:

1
systemd-resolved (most distros): sudo resolvectl flush-caches.
2
Older systemd: sudo systemd-resolve --flush-caches.
3
nscd: sudo systemctl restart nscd (or sudo nscd -i hosts).
4
dnsmasq: sudo systemctl restart dnsmasq.
5
Local BIND: sudo rndc flush.

Then verify with resolvectl query myproject.test or dig myproject.test.

Does Linux even cache DNS?

Plain glibc has no DNS cache, so editing /etc/hosts takes effect immediately. A cache exists only when you run a caching layer: systemd-resolved, nscd, dnsmasq, or a local resolver. If unsure which you use:

BASH
resolvectl status
systemctl is-active systemd-resolved nscd dnsmasq

When to flush

  • You edited /etc/hosts and a tool still resolves the old IP.
  • You changed /etc/resolv.conf or your DNS server.
  • You moved a staging site to a new server before propagation.

For editing the file itself, see how to edit the hosts file on Linux or the Ubuntu-specific guide.

Verify the result

BASH
resolvectl query myproject.test
dig myproject.test
getent hosts myproject.test

getent hosts reflects the full name-service stack, including /etc/hosts.

Troubleshooting

  • resolvectl not found: your system may not use systemd-resolved; use the nscd/dnsmasq command instead.
  • Still cached in the browser: clear the browser DNS cache and retry in a new tab.
  • WSL2: flush on the Windows host too with ipconfig /flushdns.

If you manage many local domains across machines, Sleezr keeps hosts entries organized and consistent across Linux, macOS and Windows.

_Last tested: June 2026 on Ubuntu 24.04, Fedora 40 and Debian 12._

Sources and further reading

Also readHow to edit the hosts file on Linux
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Frequently Asked Questions

How do I flush DNS on Linux with systemd-resolved?

Run sudo resolvectl flush-caches (older systems: sudo systemd-resolve --flush-caches).

Does Linux always cache DNS?

Not always. Plain glibc has no cache. Caching exists only if you run systemd-resolved, nscd, dnsmasq, or a local BIND resolver.

How do I flush dnsmasq?

Restart the service: sudo systemctl restart dnsmasq (or send SIGHUP to the dnsmasq process).

How do I verify the cache was cleared?

Use resolvectl query yourdomain.test or dig yourdomain.test and confirm the expected IP.

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