99-vpn-ipv6-switch.sh

#!/bin/bash

# https://askubuntu.com/a/1178685

# Args
INTERFACE=$1
ACTION=$2

# Check if the OpenVPN interface will be indeed tun0!
if [ "$INTERFACE" = "tun0" ]; then
  case $ACTION in
  up)
    for disabledProperty in $(sysctl -a | grep ipv6 | grep disable | sed 's/ \= 0/=1/'); do
      sysctl -w "$disabledProperty"
    done
    ;;
  down)
    for enabledProperty in $(sysctl -a | grep ipv6 | grep disable | sed 's/ \= 1/\=0/'); do
      sysctl -w "$enabledProperty"
    done
    ;;
  esac
fi