centos7 禁用IPV6

 vi /etc/default/grub
GRUB_CMDLINE_LINUX="ipv6.disable=1 
grub2-mkconfig -o /boot/grub2/grub.cfg

vi /etc/sysctl.conf

net.ipv6.conf.all.disable_ipv6=1
:wq

vi /etc/sysconfig/network

NETWORKING_IPV6=no
:wq

vi /etc/sysconfig/network-scripts/ifcfg-eth0

IPV6INIT=no
:wq
sysctl -p

reboot
cat /proc/sys/net/ipv6/conf/all/disable_ipv6

reboot