#!/bin/bash
RELAY_6TO4=192.88.99.1
IPV4=$(ip route get ${RELAY_6TO4} | head -n1 | sed 's/.*src \([0-9 ]\+\)*/\1/')
echo $IPV4
prefix=$(printf "2002:%02x%02x:%02x%02x::1\n" `echo $IPV4 | tr . ' '`)/16
echo $prefix
ip tunnel add 6to4 mode sit remote any local ${IPV4} ttl 63
ip link set 6to4 mtu 1472 up
ip addr add "$prefix" dev 6to4
ip -6 route add 2000::/3 via ::${RELAY_6TO4}