Cambiar/Modificar el default gateway/router

# more /etc/sysconfig/network-scripts/ifcfg-eth0
HWADDR=00:50:56:XX:XX:XX
NAME=eth0
DNS1=192.168.xxx.xxx
DNS2=10.82.xxx.xxx
DOMAIN="midominio.com"
DEVICE=eth0
ONBOOT=yes
USERCTL=no
BOOTPROTO=none

check_link_down() {
 return 1;
}
TYPE=Ethernet
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=no
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65xxxxx
IPADDR=10.150.xxx.xxx
PREFIX=16
GATEWAY=10.150.yyy.yyy

# nmcli con mod eth0 ipv4.gateway 10.150.zzz.zzz
# nmcli con up eth0
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)

# ip r
default via 10.150.zzz.zzz dev eth0  proto static  metric 100
10.150.0.0/16 dev eth0  proto kernel  scope link  src 10.150.xxx.xxx  metric 100