Disable IPv6

How to Disable IPv6 in Ubuntu 16.04 Xenial Xerus

Check to see if IPv6 is already disabled.

  cat /proc/sys/net/ipv6/conf/all/disable_ipv6
  # 0 = activated ; 1 = desactivated

Add those three lines. vim /etc/sysctl.conf

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

Apply the new settings.

  sudo sysctl -p
#ou
  sysctl --system

Verify the results

  cat /proc/sys/net/ipv6/conf/all/disable_ipv6

Best to reboot right now.

  reboot