I have one Linux desktop with two NICs, a wireless router, and internet access.
The Linux box's eth0 is set to connect to the internet. Its IP address is assigned by the ISP, via DHCP.
Eth1 is connected to my router, a Linksys E1000. Eth1's IP address is 192.168.1.12, and the router's IP address is 192.168.1.1.
I need all devices that connect to the router to access the internet, but I don't know how to configure the router and eth1. I'm lacking in network knowledge, and I don't know how to bridge between the two NICs so both can share internet access.
FYI, The desktop is using Ubuntu 10.04. DNS service is installed on the desktop; I'm using BIND 9. For DHCP server, it is built in on the router side.
I tested this setup using my laptop. Connected to the router, I can open web apps on the desktop at 192.168.1.12, but cannot connect to the internet.
Some might suggest that I should connect the internet connection and everything else to the router. That way is easy, but I want full control over all internet access. Next I want to learn to set up a captive portal.
How should I configure eth0, eth1 and the router so it can share the internet connection? And are there any another tools that need to be installed?