I have a Linux firewall with 3 NIC's. Eth1 is my LAN's default gateway and has IP address 10.1.2.250 and is connected to my LAN with IP range 10.1.2.0/24. Eth2 has IP address of 10.0.0.6 and gateway is 10.0.0.2 which is eth1's gateway and connected to a DSL modem. The DSL modem connects to the internet with a dial-up script on the Linux firewall and gets assigned a dynamic IP on its ppp0 interface.
Eth0 is connected to a second modem with a static public IP. Eth0 is also assigned a public IP in the range specified by the service provider.
I have a web server on one of the internal pc's on the lan on IP 10.1.2.21. The public has to be able to connect to the web server on the static public IP. I tried some IPTABLES rules such as DNAT, MASQUERADE with no luck. Maybe I am missing something. Can someone direct me to some sort of solution?