About LAN Bridges
A local area network bridge logically combines multiple interfaces to operate as a single network, with a single interface name and IP address. You configure the interface IP address and other interface settings in the bridge configuration, and then configure interfaces as members of the bridge. A bridge must include at least one interface, and can include any combination of physical, wireless, and link aggregation interfaces.
You can configure a bridge in the trusted, optional, or custom security zone. The configuration settings for a bridge are similar to the settings for any other trusted, optional, or custom network interface. For example, you can configure DHCP to give IP addresses to clients on a bridge, or use the bridge name as an alias in firewall policies.
For information about how to configure interfaces as a bridge, see Create a Network Bridge Configuration
If you want all of the Firebox interfaces to be on the same network, we recommend that you use bridge mode for your network configuration.