Monday, January 04, 2010

How to Flush DNS - Windows, Mac, iPhone

I seem to always forget what the commands are to flush the DNS on your Mac and iPhone.
I have Bell South or AT&T and occasionally I have a DNS issue such as a new or revised domain that I am unable to access. This occurs when a website is moved or there are other technical issues. If there is a website on the pubic Internet that you are not able to access, you should try Flushing your DNS. Here are instructions to do so.

If this does not work, you might also try changing your DNS from AT&T DNS to the the free http://www.opendns.com/
. Use the free IP Addresses on that page. Don't forget to change it back later since the free version of OpenDNS.com might not be reliable enough for you to use all the time.


Microsoft Windows - How to Flush DNS

C:\>ipconfig /flushdns


You can also use the command ipconfig /displaydns to view the DNS resolver cache.


Mac Leopard - How to Flush DNS

Step 1 – Open the Terminal.app

Either by start typing Terminal on the Spotlight, or by going into Applications -> Utilities -> Terminal.

Step 2 – Flush the DNS cache

On Leopard you can issue a simple Terminal command to flush the DNS cache, and have your host file changes to take immediate effect: view source print?

1.$ dscacheutil -flushcache


iPhone - How to Flush DNS

Step 1 - Turn iPhone off and turn it on again. Press and hold the Sleep/Wake button on top of iPhone for a few seconds until a red slider appears, and then slide the slider. Then press and hold the Sleep/Wake button until the Apple logo appears.

Step 2 - Reload your iPhone Safari page.

1 comment:

McGehee said...

I tried the iPhone reboot method you offered but it didn't work. After some more looking around I decided to try turning off WiFi and reloading the URL over the AT&T network instead.

That worked, and carried over when I went back to WiFi.