To change the name servers in Mac OS X:
1) Go to your Apple menu and select ‘System Preferences’.
2) Open the ‘Network’ icon
3) Highlight your connection type in the left column
4) Click the “Advanced” button
5) You can specify the name servers on the “DNS” tab. For DNS servers to use – see this Article on Best Free and Public DNS servers.
6) Click OK to save the settings.