You need an "interface route" for every interface, that is: a route with the network your interface is in as destination and your interfaces adress as gateway.

Example: you have an interface with the adress 192.168.1.100 which is part of the network 192.168.1/24. Add a route to destination network 192.168.1.0 with gateway 192.168.1.100.

As you have two interfaces you should have two of these interface routes, one for each interface. You then should define a "default route", which is a catch-all for every packet not already dealt with by the interface routes. This route should point to a gateway router on one of the networks you already participate in with your interfaces.

I can't understand what a static route between your interfaces (from eth0 to eth1 or vice versa) is supposed to achieve. If you want to send packets coming in on one interface over to the other network: this is the functionality of a router/gateway. Switch on IP-forwarding to accomplish this but be careful to understand what you are doing when you do this. You might easily compromise any network security by doing so.

bakunin