IPv6 is newer version of IP Address. It is ugly, hard to remember lol

To list IPv6 address configured on your computer, run

ip -6 addr

Disable IPv6 On CentOS 7

Edit file

vi /etc/sysctl.conf

Add following

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

Now run

sysctl -p

Temp Disable IPv6

echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6

On reboot IPv6 get activate again, unless you add above line to /etc/rc.local