1. Go to System Preferences.
4. Select the DNS tab and add 208.67.222.222 and 208.67.220.220 to the list of DNS servers. Click OK
Note: If there are any greyed out IP numbers they can be ignored.
5. Cache Flushing
At the point, we highly suggest that you flush your DNS resolver cache and web browser caches to ensure that your new DNS configuration settings take immediate effect.