EA Sports F1 Racing Sim. Through My Firewall

[Floog]

This problem is driving me crazy and I'm hoping someone can come up with an idea that I haven't thought of.

Here's the network setup:

Linux box is a router and firewall for my home LAN.
eth0 goes out to the cable modem/internet and connects with dynamic ip by way of dhcp.
eth1 has a static local ip address (199.201.13.1) and acts as the gateway to my home LAN.
I have a WinXP box on the LAN with static ip address 199.201.13.11.

Here's the problem:

Using the following set of rules I used to be able to host EA Sports F1 2002 Races over the net on the WinXP box:

echo " FWD: Allow all connections OUT and only existing and related ones IN"
$IPTABLES -A FORWARD -i eth0 -o eth1 -j ACCEPT
$IPTABLES -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -i eth1 -o eth0 -j ACCEPT

echo " Rule to let all NEW packets come in through eth0"
$IPTABLES -A INPUT -m state --state NEW -j ACCEPT #####-m state --state NEW -j ACCEPT

echo " Enabling SNAT (MASQUERADE) functionality on eth0"
$IPTABLES -t nat -A POSTROUTING -o eth0 -j MASQUERADE

echo " Enable Port Forwarding for Shareaza"
$IPTABLES -t nat -A PREROUTING -p tcp --dport 6346 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p udp --dport 6346 -i eth0 -j DNAT --to-destination 199.201.13.11

echo " Open Ports to Host EA Sports Formula 1 Racing Games over the net"

$IPTABLES -t nat -A PREROUTING -p tcp --dport 1038 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1039 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1040 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1041 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1042 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1043 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1044 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1045 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1046 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 1047 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32811 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32812 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32813 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32814 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32815 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32816 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32817 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32818 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32819 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32820 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32821 -i eth0 -j DNAT --to-destination 199.201.13.11
$IPTABLES -t nat -A PREROUTING -p tcp --dport 32822 -i eth0 -j DNAT --to-destination 199.201.13.11


I chose the ports above by joining other racing servers and recording all the ports used with tcpdump.

Well, I'm now using the latest EA Sports F1 Racing Sim., it's called F1 Challenge '99-'02 and my firewall setup no longer works and I can't host any races. I've tested it with all my racing pals and no one can see my Host over the internet.

Can anyone suggest some things to try? If you've hosted internet games through a linux router/firewall, please give me some troubleshooting tips or other suggestions.

Thank you very much for your time and patience.

Floog