But, what does bridge mode mean?
A bridge is a way to connect two network segments, but unlike routing, in a bridge packets are forwarded at Layer 2 (Ethernet), so all protocols can go transparently through it. This is very useful if you want to insert a firewall into an already working network without reconfiguring anything (clients IP addresses nor gateway).</p>
A typical scenario for a bridge is filtering traffic from one network segment (internal LAN) to another (Internet), for example, firewall and content filtering on web access through a HTTP proxy.
eBox as bridge
Let’s see some screenshots on how to set up a bridge using eBox. First of all we have to configure network interfaces that will be bridged. When doing this on the first interface a new bridge will be automatically created (br1).</p>
After that all you need is to add the other interfaces to the bridge. Don't forget to mark whether they are external or internal!