+run ip6tables -A FORWARD -j ACCEPT \
+ -p tcp --destination-port $port_ssh \
+ -m ipv6header --soft ! --header frag \
+ -m mark --mark $to_untrusted/$MASK_TO
+run ip6tables -A FORWARD -j ACCEPT \
+ -p tcp --source-port $port_ssh \
+ -m ipv6header --soft ! --header frag \
+ -m mark --mark $from_untrusted/$MASK_FROM \
+ -m state --state ESTABLISHED
+
+m4_divert(60)m4_dnl
+###--------------------------------------------------------------------------
+### Kill things we don't understand properly.
+###
+### I don't like having to do this, but since I don't know how to do proper
+### multicast filtering, I'm just going to ban it from being forwarded.
+
+errorchain poorly-understood REJECT
+
+## Ban multicast destination addresses in forwarding.
+run iptables -A FORWARD -g poorly-understood \
+ -d 224.0.0.0/4
+run ip6tables -A FORWARD -g poorly-understood \
+ -d ff::/8