hi, i tried to build a linux firewall using Centos 5.4 but not sucessfully.
Topology:

RangeIP Public <--->Firewall<--->HTTP Server

1. Firewall server includes 2 NIC:
NIC 01 have 2 IP public 64.34.34.1&2
NIC 02 has 1 internal IP 10.0.0.1
2. HTTP Server include 1 NIC
NIC 1: 10.0.0.2

I want to config to every body from internet can access to webserver (10.0.0.2) through firewall server.

Use Iptables, i try to write rules on FireWall Server bellow:
#iptables -t nat -A PREROUTING -t tcp -i eth0 --dport 80 -d <IP PUBLIC> -j DNAT --to 10.0.0.2:80
#iptables -t nat -A POSTROUTING -t tcp -s 10.0.0.2 -j SNAT --to <IP PUBLIC>

But not sucessfully. Please help me !

This might give you a few hints and ideas: IPTABLES Firewall Example