You can enter the resolver IP address as steps mentioned below :
From WHM of your VPS/Dedicated Server :
Login to WHM. (http ://youripaddress:2086). Click on Resolver configuration under Networking Setup.
It will show the default resolver of our DataCenter IP address. Enter the IP addresses of at least two nameservers that you will use for DNS resolution.
From SSH of your VPS/Dedicated Server :
You can also do it manually via SSH from /etc/resolv.conf file, if you have a shell access of your server.
1) Open /etc/resolv.conf file using any text editor that you are familiar with e.g vi, pico or nano
2) Add the IP addresses provided by your server provider.
3) Save file.