iptables -t raw -N CONNTRACK
iptables -t raw -A PREROUTING -j CONNTRACK
+ # Restore any connection marks
+ iptables -t mangle -A PREROUTING -j CONNMARK --restore-mark
+
# Fix for braindead ISPs
iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu