Removing DNS settings from your Mac OS X machine
Click on the Apple Logo located at the top left hand corner of your Mac and open System Preferences.
Navigate to Internet & Wireless and click on Network.
Select your active Internet Adapter (Airport if Wireless or Ethernet if Wired) and click Advanced.
Navigate to the DNS tab, select the DNS addresses that appears in the DNS field and click on the minus (-) button to remove them.
Click OK to save the changes.
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