You need to activate your IP address to start using SmartDNS. Login to Client Area, go to Services -> View Details and click on Update IP button. IP address needs to be updated every time it changes.
Open System Preferences
Click on Network under Internet & Wireless
Select the network (Wireless or Ethernet) your Mac is connected to and click on Advanced.
Select the DNS tab on the top section.
Click on + (plus) button on the bottom left side of the screen and type the: Preferred DNS Server.
Click on + button again and type the: Alternate DNS Server.
Click OK and restart your computer.
*Using the closest location will give you better speed of dns resolution.
Preferred DNS Server: 184.108.40.206
Alternate DNS Server: 220.127.116.11
Preferred DNS Server: 18.104.22.168
Alternate DNS Server: 22.214.171.124