## Deploy SYN-cookies if necessary.
setopt tcp_syncookies 1
+## Allow broadcast and multicast ping, because it's a useful diagnostic tool.
+setopt icmp_echo_ignore_broadcasts 0
+
+## Turn off iptables filtering for bridges. We'll use ebtables if we need
+## to; but right now the model is that we do filtering at the borders, and
+## are tolerant of things which are local.
+if [ -x /sbin/brctl ]; then
+ modprobe bridge || :
+ if [ -d /proc/sys/net/bridge ]; then
+ for filter in arptables iptables ip6tables; do
+ run sysctl -q net.bridge.bridge-nf-call-$filter=0
+ done
+ fi
+fi
+
## Turn on the reverse-path filter, and log weird things.
-setdevopt rp_filter 1
-setdevopt log_martians 1
+setdevopt rp_filter $rp_filter
+setdevopt log_martians $log_martians
## Turn off things which can mess with our routing decisions.
setdevopt accept_source_route 0
m4_divert(36)m4_dnl
###--------------------------------------------------------------------------
-### Standard loopback stuff.
+### Standard filtering.
## Don't clobber local traffic
run ip46tables -A INPUT -i lo -j ACCEPT
run ip6tables -A FORWARD -g bad-destination-address \
-d fe80::/10
+## Also, don't forward link-local broadcast or multicast.
+run iptables -A FORWARD -g bad-destination-address \
+ -d 255.255.255.255
+run iptables -A FORWARD -g bad-destination-address \
+ -m addrtype --dst-type BROADCAST
+run iptables -A FORWARD -g bad-destination-address \
+ -d 224.0.0.0/24
+for x in 0 1 2 3 4 5 6 7 8 9 a b c d e f; do
+ run ip6tables -A FORWARD -g bad-destination-address \
+ -d fe${x}2::/16
+done
+
+## Add a hook for fail2ban.
+clearchain fail2ban
+run ip46tables -A INPUT -j fail2ban
+
m4_divert(90)m4_dnl
###--------------------------------------------------------------------------
### Finishing touches.
m4_divert(94)m4_dnl
## Locally generated packets are all OK.
-run iptables -P OUTPUT ACCEPT
+run ip46tables -P OUTPUT ACCEPT
## Other incoming things are forbidden.
for chain in INPUT FORWARD; do
- run iptables -A $chain -g forbidden
+ run ip46tables -A $chain -g forbidden
done
m4_divert(-1)