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.
Click the "Network Manager" icon in your menu bar, and then click the Edit Connections
Select the "Wired" or "Wireless" tabs, depending on your type of connection, then select the network you're connected to and click "Edit"
Select the "IPv4 Settings" tab and change "Method" to "Automatic (DHCP) addresses only".
Insert our DNS addresses to the "DNS Server" section separated by comma
*Using the closest location will give you better speed of dns resolution.
Preferred DNS Server: 188.8.131.52
Alternate DNS Server: 184.108.40.206
Preferred DNS Server: 220.127.116.11
Alternate DNS Server: 18.104.22.168