Comments on: How To Flush Linux / UNIX DNS Cache

By: david.chen

david.chen — Fri, 03 Feb 2012 02:45:19 +0000

why not just use
nscd -i hosts
nscd -i passwd .
to flush the cache

By: m4h

m4h — Thu, 15 Sep 2011 08:10:24 +0000

Manish ->

Change from:
192.168.1.1 admin.domain.com admin
TO:
192.168.1.1 admin admin.domain.com admin

By: Tricky

Tricky — Sun, 10 Apr 2011 11:58:50 +0000

@takprosto
Do the commands give an error or are they just not refreshing the DNS? If there’s no error then the DNS entry could be cached elsewhere, for example on your router or your ISP’s DNS server.

By: takprosto

takprosto — Sat, 09 Apr 2011 23:45:46 +0000

Im sorry for my bad english…. but im have Debian.
apt-get install nscd Ok
-d, –debug Do not fork and display messages on the current tty
-f, –config-file=NAME Read configuration data from NAME
-g, –statistic Print current configuration statistic
-i, –invalidate=TABLE Invalidate the specified cache
-K, –shutdown Shut the server down
-t, –nthreads=NUMBER Start NUMBER threads
–usage Give a short usage message

commands restart and reload not work ! haven`t ))) and -shutdown not work

By: nobbiecentos

nobbiecentos — Tue, 08 Feb 2011 13:15:17 +0000

TY for information its working solution for clear cash from server side

By: Lost Eagle

Lost Eagle — Mon, 31 Jan 2011 16:01:16 +0000

Thank U

This “rndc flush” help lot … restart doesn’t flush …

Have a nice day

By: Tricky

Tricky — Mon, 06 Dec 2010 03:49:29 +0000

host doesn't bother with the entries in the hosts file. Try ping admin instead.

By: Manish

Manish — Sat, 04 Dec 2010 18:49:25 +0000

I have a local name resolution issues on CentOS 5.5. I have edited the /etc/hosts file and still the hostname doesn’t resolves to right IP.

Here is what I have priority configuration
# more /etc/host.conf
order hosts,bind
Also /etc/nsswitch.conf file has

hosts: files dns
more /etc/hosts
192.168.1.1 admin.domain.com admin

# host admin
Host admin not found: 3(NXDOMAIN)

Any suggestions would be appreciated.

By: Tricky

Tricky — Fri, 03 Sep 2010 04:48:30 +0000

@Yogesh. Chances are the DNS is cached outside of your desktop or the DNS is being cached by an application directly.

I wrote an (admittedly regex-cryptic) article on this same issue (sorry for the “competing” link, Vivek) – http://dogma.swiftspirit.co.za/archives/300 – skip to the sections after the label “Flush Mozilla Firefox’s internal DNS cache”.

By: Yogesh

Yogesh — Thu, 02 Sep 2010 15:32:20 +0000

@Tricky
Thanks for comment, but I am unable to find /etc/init.d/nscd or named on my Centos 5.3 Desktop. Any help?

By: Tricky

Tricky — Thu, 02 Sep 2010 14:14:28 +0000

@Yogesh: The same commands apply to a desktop

@dejf: Bear in mind per my comment above, perhaps your desktop has a separate DNS cache or the DNS is being cached elsewhere. You have to flush the DNS on all your “upstream” DNS servers as well or change the DNS servers that you’re using.
See the following for info on how to change your DNS settings to these 2 popular public DNS servers:
http://code.google.com/speed/public-dns/
https://store.opendns.com/setup/router/

By: Yogesh

Yogesh — Thu, 02 Sep 2010 12:08:02 +0000

I guess this is for DNS server. What shall I do if I wish to clear DNS cache on a linux client/desktop machine? [Like ipconfig /flushdns in windows]

By: dejf

dejf — Tue, 31 Aug 2010 15:04:55 +0000

“/etc/init.d/dnsmasq restart” do not work, even stop and start does not. There is a clear cache option entioned, but it does not help anyway – dnsmasq remembers…

By: Subhash

Subhash — Tue, 27 Jul 2010 17:26:40 +0000

That is correct!

By: takizo

takizo — Mon, 26 Jul 2010 14:58:10 +0000

it could be nscd is not install?

@James, rndc reload works too :D

By: Tricky

Tricky — Sun, 26 Apr 2009 23:50:17 +0000

If nscd is in use, try “nscd -i hosts” as root.
As per James Mills, “rndc flush” if using bind.

If none of these work you might not have a DNS cache to flush anyway and the problem DNS entry may be stored elsewhere, such as your firefox DNS cache, your router’s cache, or another upstream DNS caching server.

By: RudyD

RudyD — Wed, 04 Feb 2009 12:35:00 +0000

Whoops!

It seems that not the perfect view for precise approach. It seems that if I use bind and there is a resolv.conf too not always the bind is in use. (Ubuntu) Other important machine (with debian), there is just resolv.conf. Anyhow I have tried to restart (hope works) the /etc/init.d/dns-clean and it seems it worked. But there were reports that this did not do the job. Anyhow, I want to make sure that – especially my debian system – without restarting, even the networking, how can I just restart the name resolution to the newly set values and how to get sure that it is done well?

Thanks!

By: James Mills

James Mills — Fri, 19 Sep 2008 08:32:03 +0000

Actually, in Bind, you can flush the daemon’s cache by doing

rndc flush

By: kazoolist

kazoolist — Thu, 10 Jul 2008 22:54:19 +0000

I my experience service nscd restart does not clear NSCD's cache. service nscd reload does, however.

By: NoPremium.org

NoPremium.org — Fri, 18 Apr 2008 08:32:09 +0000

it dont work for me i have ubunu 7.10