I am using Ubuntu 14.04. And I have done the following to disable ipv6. I have open /etc/sysctl.conf using gedit and paste the following lines at the end of sysctl.conf. net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1 But when I check it using following command, $ cat /proc/sys/net/ipv6/conf/all/disable_ipv6 I am getting result as '0'( i.