Well, it took some time, but I got it to work finally. I still have a small problem, but more on that later…
I installed tinyproxy, and after tinkering with its configuration files, I’m now able to share my filtered internet connection through the router
I will play with it some more to figure out all what I need, but I think I have got my self a solution, THANKS Caeda!!
Now for the problem: because I have two NICs on my proxy PC, two servers answer DHCP requests: the DSL modem, and my router, and they overwrite each others DNS and routing table info.
so my internet connection get messed up.
I tried to setup /etc/iftab so that I have the eth1 and eth2 fixed and not switching around every boot (which worked so far) and then setup /etc/network/interfaces so that only my modem facing NIC will use DHCP, while the router facing NIC uses static IP setup, still it didn’t work, I had to disconnect my router and lunch dhclient and reconnect my router when finished in order to fix the internet connection. Another reason I want a static ip on the router facing NIC is that I don't want to change my browser settings everytime the IP address change.
What can I do to fix this issue?