I have no idea... but it is probably the reason it's not working. To verify, we need another device to test the theory. Thus the DD-WRT unit.
Well I realize that I can do more with the DD-WRT router software which is one reason I like the open source software, but I’m definitely going to need help with verifying the settings.
for DD-WRT, please visit the DD-WRT forums. That firmware is not at all related to OpenWrt and is not supported here.
I'm simply suggesting that you try DD-WRT instead of the Belkin device as a test, but help with DD-WRT is out of scope for this forum.
Well i just need to know some basic things cause it does give the options to set it as a gateway and a router.
Gateway is the same thing as a router.
Just reset the DD-WRT device to its default configuration. IIRC, the default subnet is 192.168.1.0/24 with active DHCP and DNS servers and it should have the wan configured as DHCP client. This should be compatible with your OpenWrt config.
Connect the wan port of the DD-WRT device to eth2 on your x86 box, and then connect another computer to one of the DD-WRT lan ports. Make sure the computer is configured to be a DHCP client and then test.