Stop NetworkManager to overwrite /etc/resolv.conf

Network manager overwrite the /etc/resolv.conf file. To stop overwriting this file. We can follwo the below steps

# systemctl disable NetworkManager.service
# systemctl stop NetworkManager.service

Or If we don't want to stop or disable the network manager service, in that case. We will have to tell NetwoekManager not to modify the DNS settings:

 /etc/NetworkManager/NetworkManager.conf
 [main]
 dns=none