Yes, when connected to our VPN service, public DNS servers are automatically assigned to your computer.This ensures that you are using public DNS servers instead of your internet service provider’s DNS Servers.
It can happen that your system for some reason reverts back to your ISP’s DNS servers.One way to test this would be connecting to the VPN and then doing a DNS leak test from http://www.dnsleaktest.com/
You can prevent DNS leaks by setting one of the below public DNS servers for all available network adapters in the TCP/IP options within the properties of your network adapters.
If you are using firefox browser and ssh tunnel/socks proxy please open about:config on firefox and scroll down until you get network.proxy.socks_remote_dns and change it to true in order to prevent dns leakage on firefox with ssh tunnel/socks proxy usage.
We also suggest disabling WebRTC and IPv6 usage.
Disabling WebRTC :
http://www.earthvpn.com/faq-items/how-to-prevent-webrtc-leaks-on-chrome-and-firefox-browsers/
Disabling IPv6 usage on windows :