run iptables -t nat -X
run iptables -t nat -N outbound
-run iptables -t nat -A outbound -j RETURN ! -o eth0
+run iptables -t nat -A outbound -j RETURN ! -o ppp0
run iptables -t nat -A outbound -j RETURN ! -s 172.29.198.0/23
run iptables -t nat -A outbound -j RETURN -d 62.49.204.144/28
run iptables -t nat -A outbound -j RETURN -d 172.29.198.0/23
run iptables -t nat -A outbound -j SNAT --to-source 62.49.204.158
run iptables -t nat -A POSTROUTING -j outbound
+## TCP MSS clamping to help given Demon's sluggish approach to fragmentation-
+## needed errors.
+run ip46tables -t mangle -A FORWARD -o ppp0 -p tcp --tcp-flags SYN,RST SYN \
+ -j TCPMSS --clamp-mss-to-pmtu
+
## Set up NAT protocol helpers. In particular, SIP needs some special
## twiddling.
run modprobe nf_conntrack_sip \
run modprobe nf_nat_$p
done
-## Forbid anything complicated to the NAT address.
+## Forbid anything complicated to the NAT address. Be sure to allow ident,
+## though.
+run iptables -A INPUT -d 62.49.204.158 -p tcp -j ACCEPT \
+ -m multiport --destination-ports=113
run iptables -A INPUT -d 62.49.204.158 ! -p icmp -j REJECT
m4_divert(-1)