A bridge is a way to connect two Ethernet segments together in a protocol independent way. Packets are forwarded based on Ethernet address, rather than IP address (like a router). Since forwarding is done at Layer 2, all protocols can go transparently through a bridge.
Bridging is supported in the current Linux kernels (2.4 and 2.6) from all the major distributions. The required administration utilities are in the bridge-utils package in most distributions.
Setup an Ethernet bridge in Debian
- Install two Ethernet LAN cards in a PC with Debian installed. The original LAN card is named "eth0" and the newly installed LAN cards are named "eth1" and "eth2".
- Install the bridge administration tools:
# apt-get install bridge-utils - Setup a bridge between eth1 and eth2 by the following commands:
# ifconfig eth1 0.0.0.0
# ifconfig eth2 0.0.0.0
# brctl addbr br0
# brctl addif br0 eth1
# brctl addif br0 eth2
# ifconfig br0 up
