IPv6 is dead,how to disable IPv6.

1)edit /etc/sysconfig/network-scripts/ifcfg-xxx
   IPV6INIT=no
   IPV6_AUTOCONF=no

2)edit /etc/sysctl.conf
    net.ipv6.conf.all.disable_ipv6 = 1
    net.ipv6.conf.default.disable_ipv6 = 1

3)ip6tables : drop all ipv6 packets.
	ip6tables -t filter -F
	ip6tables -t filter -X
	ip6tables -t filter -Z
	ip6tables -t filter -P INPUT DROP
	ip6tables -t filter -P FORWARD DROP
	ip6tables -t filter -P OUTPUT DROP
	ip6tables -t raw -F
	ip6tables -t raw -X
	ip6tables -t raw -Z
	ip6tables -t raw -P PREROUTING DROP
	ip6tables -t raw -P OUTPUT DROP
	ip6tables -t mangle -F
	ip6tables -t mangle -X
	ip6tables -t mangle -Z
	ip6tables -t mangle -P PREROUTING DROP
	ip6tables -t mangle -P POSTROUTING DROP
	ip6tables -t mangle -P INPUT DROP
	ip6tables -t mangle -P OUTPUT DROP
	ip6tables -t mangle -P FORWARD DROP

  sudo vmstat -m
    TCPv6
    UDPv6
      ==> ipv6 is running in the kernel.

4)edit /boot/grub2/grub.cfg
  add ipv6.disable=1
   linux /vmlinuz-3.11.7-200.fc19.x86_64 root=UUID=df322796-... ro ipv6.disable=1 ...
  reboot 

5)Fedora
   vi /etc/default/grub
      GRUB_CMDLINE_LINUX="ipv6.disable=1  ...
   # reload
   sudo /sbin/grub2-mkconfig -o /boot/grub2/grub.cfg
   reboot 

   sudo vmstat -m
      ipv6 isn't running in the kernel.