1. Ubuntu/Debian/Centos

    Edit the /etc/sysctl.conf file.

     – sudo nano /etc/sysctl.conf

   Place the following entry to disable IPv6 for all adapters.

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

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

     – net.ipv6.conf.lo.disable_ipv6 = 1

   To reflect the changes execute the following command.

     – sudo sysctl -p