#ping不通cf的dns地址就执行……
if [ $(ping -c 2 2606:4700:4700::1111 | grep from* | wc -l) -eq 0 ]; then
ip link set dev eth0 down
ip link set dev eth0 up
ip address flush dev eth0
ip -6 address add 2001:10::4/64 dev eth0
ip -6 route add default via fe80::1234:5678:9abc dev eth0
fi