=====how to disable ipv6=====
verify ipv6 with:
  ip address
  
before and after the issue of the following command

  sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
  sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
  sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=1