To specify the new domain name server, you will need to edit the file resolv.conf. Open the file with any text editor:
nano /etc/resolv.conf
and replace the ip-address with a new one in the line nameserver:
# Generated by NetworkManager
search fornex.cloud
nameserver 91.228.153.88
nameserver 212.224.118.111
Also, to keep your settings intact after a reboot, you will need to make changes to the network interface configuration file:
nano /etc/sysconfig/network-scripts/ifcfg-eth0
Enter the new ip on the lines:
DNS1=91.228.153.88
DNS2=212.224.118.111