Disable IPv6

[root@isbyeon ~]# ifconfig | grep "inet6 addr"

inet6 addr: 2001:320:3107:1005:a00:27ff:fe50:34b4/64 Scope:Global
inet6 addr: fe80::a00:27ff:fe50:34b4/64 Scope:Link
inet6 addr: ::1/128 Scope:Host

[root@isbyeon ~]# echo "install ipv6 /bin/true" > /etc/modprobe.d/disable-ipv6.conf
[root@isbyeon ~]# sync;sync;sync;reboot
[root@isbyeon ~]# ifconfig | grep "inet6 addr"