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BRIDGE(4) FreeBSD Kernel Interfaces Manual BRIDGE(4) NAME bridge -- bridging support SYNOPSIS options BRIDGE DESCRIPTION FreeBSD supports bridging on Ethernet-type interfaces. Runtime operation of the bridge is controlled by several sysctl(8) vari- ables. The net.link.ether.bridge variable can be set to 1 to enable bridging, or set to 0 to disable it. The net.link.ether.bridge_ipfw variable can be set to 1 to enable ipfw(8) filtering on bridged packets. Note that ipfw(8) rules only apply to IP packets. Non-IP packets are subject to the default ipfw(8) rule (number 65535) which must be an allow rule if ARP and other non-IP packets need to flow through the bridge. The bridge configuration is controlled by the net.link.ether.bridge_cfg variable. It consists of a comma-separated list of interface:cluster pairs, where all interfaces with the same cluster number will be bridged together. Another variable reinitializes the bridge; this is required if bridged configurations include loadable interfaces. After loading new interface drivers, setting the net.link.ether.bridge_refresh variable to 1 will cause the bridge to reinitialize itself. EXAMPLES The following command will cause the ep0 and fxp0 interfaces to be bridged together, and the fxp1 and de0 interfaces to be bridged together: sysctl net.link.ether.bridge_cfg=ep0:0,fxp0:0,fxp1:1,de0:1 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. Interfaces that cannot be put into promiscuous mode or that don't support sending packets with arbitrary Ethernet source addresses are not compati- ble with bridging. SEE ALSO ip(4), ng_bridge(4), ipfw(8), sysctl(8) HISTORY bridge bridging was introduced in FreeBSD 2.2.8 by Luigi Rizzo <luigi@iet.unipi.it>. FreeBSD 11.1 September 28, 1998 FreeBSD 11.1
NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | BUGS | SEE ALSO | HISTORY
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