In order to use the ethernet bridging functionality you'll need the userspace tools available at http://www.math.leidenuniv.nl/~buytenh/bridge. The tarball available there contains extensive documentation, but if you still have questions, don't hesitate to post to the mailing list (more info at http://www.math.leidenuniv.nl/mailman/listinfo/bridge). You can also mail me at buytenh@gnu.org. Lennert Buytenhek