How to Port Forward Using IPtables - my first try

Hi

I am playing around with IPtables for the first time (on a Debian Lenny box) and I am having some trouble - It is a bit of a learning curb for me :P

What I want to achieve is making an internal application (on a local/internal Windows server) that has a web front-end externally available, so that my users can access it from anywhere with an internet connection.

The Debian box has two network interfaces - the one has a static IP that is externally accessible (tested and confirmed that the server is accessible on the IP) - eth1 with 196.211.X.X and the other interface is for my internal network eth0 on IP 10.47.134.11. The server who is running the web front-end I want made available is running on 10.47.134.36.

My IPTABLES doesn't have any rules set and it accepts all connections (for now while I am testing - I will be restricting access as soon as I got the port forwarding working).

I add the port FOWARD on IPtables as follows (I tried 2 different IPtables setups for the port fowards):
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iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 80 -j DNAT --to 10.47.134.36:80
iptables -A INPUT -p tcp -m state --state NEW --dport 80 -i eth1 -j ACCEPT
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iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 80 -j DNAT --to 10.47.134.36:80
iptables -A FORWARD -p tcp -m state --state NEW -d 10.47.134.36 --dport 80 -j ACCEPT
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With both the setups above the results were the same when trying to access the the static IP on port 80 from a web browser --- "Network Timeout - The server at 196.211.X.X is taking too long to respond."

Is one of the port forward setups I used correct, or should I be setting the rules differently - Is there log files maybe that can give more info on the IPtables traffic - or is there something else wrong that I should be looking at?

THX in advance
Hendrik