HOWTO: flush / clean DNS cache in Linux

Sometimes your system caches too much on DNS query / records.

DNS caching helps alot on reducing time and bandwidth when your application needs DNS informations, but just like anything else in the world; it’s not a good thing when it does too over.

Let’s see how to flush DNS cache in your system.

In Ubuntu:

$ sudo /etc/init.d/dns-clean restart

For Others:

Flush nscd DNS cache:

$ sudo /etc/init.d/nscd restart


$ sudo service nscd restart


$ sudo service nscd reload


$ sudo nscd -i hosts

Flush dnsmasq dns cache

$ sudo /etc/init.d/dnsmasq restart

Flush caching BIND server dns cache

$ sudo /etc/init.d/named restart


$ sudo rndc flush

Refs: How To Flush Linux / UNIX DNS Cache

Originally published at on September 24, 2009.


BlueT’s LoGeeks, Logics of Geeky Thoughts.

BlueT / Matthew Lien 練喆明

Written by

Just another Perl / OpenSource / Security Hacker. CTO / Co-founder @Imonology, Leader @Ubuntu_TW, Founder @OSSPlanet. Promote Ubuntu Linux, Networking, Privacy.



BlueT’s LoGeeks, Logics of Geeky Thoughts.

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