Port Forwarding Need help

[nitin mandolkar]

Need Help in port forwaeding.

This is my set up.

                  DSL ROUTER (WAN IP : x.x.x.x | LAN IP 192.168.5.1)

                                              |
                                              |
                                              |
                 Linux Machine (eth0: 192.168.0.2 eth1: 192.168.5.12)
                                              |
                                              |
                                              |
                 Windows machine(eth1: 192.168.5.4)(IIS is running on
                 this machine on port 80)                    

                From router i am forwarding the request to linux
machine to port 80.
                any one from out site they are able to see a test
pages on linux
                machine.
              
              i want to forward any request coming on port 80 on linux
machine to
               windows machine on port 80.
  

/sbin/iptables -A PREROUTING -t nat -p tcp -s 192.168.5.1 -d
192.168.5.12 --dport 80  -j DNAT --to-destination  192.168.5.4:80

I Use above iptables entry but it is not working.

Nitin mandolkar.