Resolv.conf

Prevent DHCP client from changing resolv.conf file

This is the method that I recommend using the most.

Edit /etc/dhcp/dhclient-enter-hooks.d/nodnsupdate.

vim /etc/dhcp/dhclient-enter-hooks.d/nodnsupdate

Make the following edits:

#!/bin/sh
make_resolv_conf(){
    :
}

Save and exit.

Update the permissions on the nodnsupdate file.

chmod +x /etc/dhcp/dhclient-enter-hooks.d/nodnsupdate

Reboot your server. You can now update nameservers by editing /etc/resolv.conf without worrying about rollback.