if you connect two computers to a switch they should be able to communicate, there addresses probably wouldnt matter.
without a switch you could set it up like:
Code:
ISP-----eth0 LINUX PC / ROUTER / DHCP SERVER eth1-------eth1 HOST
or with a switch:
Code:
ISP-----eth0 LINUX PC / ROUTER / DHCP SERVER eth1------SWITCH-----eth1 HOST
