BRIDGE(4)

NAME
bridge - Bridging support

DESCRIPTION
Starting from version 2.2.8, FreeBSD supports bridging on ethernet-type interfaces. This is achieved using the following option

        options BRIDGE

in the kernel config file, and is controlled by two sysctl variables:

        net.link.ether.bridge

Set to 1 to enable bridging, set to 0 to disable it

        net.link.ether.bridge_ipfw

Set to 1 to enable ipfw filtering on bridged packets.

BUGS

Care must be taken not to construct loops in the bridge topology. The kernel supports only a primitive form of loop detection, by disabling some interfaces when a loop is detected. No support for a daemon running the spanning tree algorithm is currently provided.

With bridging active, interfaces are in promiscuous mode, thus causing some load on the system to receive and filter out undesired traffic.

Extended functionality to enable bridging selectively on clusters of interfaces is still in the works.

Not all interface support bridging -- at the moment it only works for ``ed'', ``de'', ``fxp'', ``lnc'' interfaces.

SEE ALSO
ip(4), ipfw(8), sysctl(8).

HISTORY
bridge bridging has been introduced in FreeBSD 2.2.8 by Luigi Rizzo <luigi@iet.unipi.it>.