1. Open "Applications" folder.
2. Open the "Utilities" folder within "Applications" menu.
3. Click "AirPort Admin Utility".
4. Select your base station from the list, then click "Configure".
5. Enter your AirPort password.
6. Click the "Internet" button.
7. Type in Safe From Sites DNS addresses in "DNS servers" fields, then click "Update" button.

 

Visit http://test.SafeFromSites.com/ to test your new settings.

You should see the Blocked Page from Safe From Sites DNS.