$SERVERIPV4ADDR == Server IPv4 address as listed on tunnelbroker.net
$CLIENTIPV4ADDR == Client IPv4 address as listed on tunnelbroker.net
$CLIENTIPV6ADDR == Client IPv6 address as listed on tunnelbroker.net
$ROUTED64 == Routed /64 as listed on tunnelbroker.net

    # IPv6 via HE tunnel...
    auto he-ipv6
    iface he-ipv6 inet6 v4tunnel
        address $CLIENTIPV6ADDR
        netmask 64
        remote $SERVERIPV4ADDR
        local $CLIENTIPV4ADDR
        endpoint any
        ttl 64
        up      ip -6 route add 2000::/3 via ::$SERVERIPV4ADDR dev he-ipv6
        up      ip -6 addr add $ROUTED64::1:1/128 dev he-ipv6
        up      ip -6 addr add $ROUTED64::2:1/128 dev he-ipv6
        down    ip -6 route flush dev he-ipv6