Clearing DNS caches

When making DNS changes it can often take a while for various DNS caches between yourself and the source to clear. I’ve often found that the last ones to change are the ones in the last few metres – from your router to your browser.

You’ll need to find the one upstream that’s incorrect and fix “backwards” from that – i.e. check your Windows DNS cache first, then work towards the browser.

Browser

According to OpenDNS, all browsers will clear their DNS cache if you use their clear cache functionality, but that’ll take out a lot more than DNS.

Chrome: Visit chrome://net-internals/#dns and press the ‘clear hosts cache’ button. You can also see what IP it’s talking to on this page.

Firefox: Close and re-open browser should do it – otherwise there’s a fiddly method involving about:config. When I’ve tried out the plug-ins I’ll add a suggestion, but if you’ve using one let me know in the comments and I’ll update this.

IE: no independent DNS cache.

Local Windows machine

At command prompt: ipconfig /flushdns

Use ping to see if you’re resolving OK.

Windows Server (if acting as DNS cache)

At command prompt: dnscommand <servername> /clearcache

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