[plug] Flushing DNS cache

[Jason Nicholls]

Check /etc/resolv.conf on your system, chances are it's set to your
router/gateway (which may or may not be caching results)

Reboot the router/gateway

Restart your web-browser and you're done.

If it's pointing to your own box then restart bind: 
/etc/init.d/bind9 restart



On Tue, Aug 04, 2009 at 12:18:49PM +1000, Daniel Pittman wrote:
> Jason Posavec <jasonposavec at iinet.net.au> writes:
> 
> > Can anybody help with an appropriate command to flush my ISP's DNS cache
> > when a particular website has changed its server details?
> 
> You can't flush the ISP DNS cache, only one that you control.  (Imagine if you
> could: anyone in the universe[1] could flush the DNS cache, costing you more
> money /and/ making you more vulnerable to attacks!)
> 
> > The Ubuntu forums have been less than helpful with "flush DNS
> > cache". Apparently the equivalent Windoze command would be ipconfig
> > /flushdns.
> 
> Linux doesn't cache by default, but various add-ons can.
> 
> If you have nscd installed, it has a command line option to flush the cache.
> 
> If you use recent bind then 'rndc flush' will do it.
> 
> 
> > And yes, if somebody was to have a guess at why I want this they'd probably
> > be right... ;)
> 
> ...however, if your browser is doing the wrong thing, restart it.  All the
> browsers have their own internal cache of DNS names that they hold on to for
> grim death in an effort to save us from security risks.[2]
> 
> Given that the *only* way to flush *their* cache is to restart the browser.
> 
>         Daniel
> 
> Footnotes: 
> [1]  ...or, even just in the subscriber base, which is identical if any one of
>      their machines is taken over.
> 
> [2]  ...and, yes, I /am/ bitter about this, and it /is/ because I get bitten
>      by it because I use a laptop that crosses a split-view DNS boundary on
>      occasion.
> 
> -- 
> ✣ Daniel Pittman            ✉ daniel at rimspace.net            ☎ +61 401 155 707
>                ♽ made with 100 percent post-consumer electrons
> _______________________________________________
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Regards,

Jason Nicholls
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Jason Nicholls                     email: <jason at mindsocket.com.au>
http://jason.mindsocket.com.au/   mobile: +61 430 314 857
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