[root@centos7 ~]# nmcli c mod ip_fixe +ipv4.dns 127.0.0.1

[root@centos7 ~]# nmcli c mod ip_fixe -ipv4.dns 8.8.8.8

[root@centos7 ~]# nmcli c up ip_fixe
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/3)

[root@centos7 ~]# cat /etc/resolv.conf 
# Generated by NetworkManager
search fenestros.loc
nameserver 127.0.0.1