In order to have the bridge working, you need to have bridging support enabled through the appropriate kernel modules. You also need to declare the driver module of the network card assigned to your internal network. In the following example, this card is supposed to be a Realtek 8139 fast Ethernet module onboard.

To configure your modules, go to the LEAF Packages configuration menu and choose modules. Enter 1) to edit the /etc/modules file and enter the following information:

(...)
# Those realtek based NICs need mii module
mii
#8139cp
8139too
# Bridge support
bridge
(...)

bridge.lrp is shipped as part of the standard Bering floppy. The bridge.lrp contains only the utilities and not the kernel module. The kernel modules for the network interface module and bridging can be downloaded from Bering module directory

Copy the modules to /lib/modules directory.

Check if they work by giving the commands as follows in the same order (important):

Bering -root-
# insmod mii

Bering -root-
# insmod 8139too

Bering -root-
# insmod bridge

These should load properly as they do not have any other dependencies.