## Since packets with source and destination addresses both local will go
## over the loopback interface, I shouldn't see a packet from me over any
## other interface. Except that I will if I sent a broadcast or multicast.
-## Allow the broadcasts, and remember not to trust them.
+## Allow the broadcasts, and remember not to trust them. There are no
+## broadcast addresses in IPv6 (only link-local multicast)m so we don't have
+## to worry about that.
run iptables -t mangle -A local-source -j RETURN \
-m addrtype --dst-type BROADCAST
run iptables -t mangle -A local-source -j RETURN \
-s $addr
done
+## It's not valid to have a multicast address as a packet source: multicast
+## routing is done away from the source, so a multicast address would make
+## this impossible to do. So discard these packets. Also discard class-E
+## IPv4 addresses, since they aren't assigned.
+run iptables -t mangle -A in-classify -g bad-source-address \
+ -s 224.0.0.0/3
+run ip6tables -t mangle -A in-classify -g bad-source-address \
+ -s ff00::/8
+
m4_divert(41)m4_dnl
## Define the important networks.
for pass in 1 2; do