.\" $NetBSD: brconfig.8,v 1.20.6.1 2024/09/05 09:27:12 martin Exp $ .\" .\" Copyright 2001 Wasabi Systems, Inc. .\" All rights reserved. .\" .\" Written by Jason R. Thorpe for Wasabi Systems, Inc. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed for the NetBSD Project by .\" Wasabi Systems, Inc. .\" 4. The name of Wasabi Systems, Inc. may not be used to endorse .\" or promote products derived from this software without specific prior .\" written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE .\" POSSIBILITY OF SUCH DAMAGE. .\" .Dd August 29, 2024 .Dt BRCONFIG 8 .Os .Sh NAME .Nm brconfig .Nd configure network bridge parameters .Sh SYNOPSIS .Nm .Fl a .Nm .Ar bridge .Nm .Ar bridge .Ar command .Op Ar args ... .Sh DESCRIPTION The .Nm utility is used to configure network bridge parameters and retrieve network bridge parameters and status from the kernel. The bridging function is implemented by the .Xr bridge 4 driver. .Pp A network bridge creates a logical link between two or more IEEE 802 networks that use the same (or .Dq similar enough ) framing format. For example, it is possible to bridge Ethernet and 802.11 networks together, but it is not possible to bridge Ethernet and Token Ring together. .Pp Bridge interfaces are created using the .Xr ifconfig 8 command's .Dq create sub-command. All other bridge configuration is performed using .Nm . .Pp The options are as follows: .Bl -tag -width indent .It Fl a Display the status of all bridge devices present on the system. This flag is mutually exclusive with all other sub-commands. .El .Pp All other operations require that a bridge be specified. If a bridge is specified with no sub-commands, the status of that bridge is displayed. The following sub-commands are available: .Bl -tag -width indent .It Cm up Start forwarding packets on the bridge. .It Cm down Stop forwarding packets on the bridge. .It Cm add Ar interface Add the interface named by .Ar interface as a member of the bridge. The interface is put into promiscuous mode so that it can receive every packet sent on the network. .It Cm delete Ar interface Remove the interface named by .Ar interface from the bridge. Promiscuous mode is disabled on the interface when it is removed from the bridge. .It Cm addr Display the addresses that have been learned by the bridge. .It Cm maxaddr Ar size Set the size of the bridge address cache to .Ar size . The default is 100 entries. .It Cm timeout Ar seconds Set the timeout of address cache entries to .Ar seconds seconds. If .Ar seconds is zero, then address cache entries will not be expired. The default is 1200 seconds. .It Cm deladdr Ar address Delete .Ar address from the address cache. .It Cm flush Delete all dynamically-learned addresses from the address cache. .It Cm flushall Delete all addresses, including static addresses, from the address cache. .It Cm discover Ar interface Mark an interface as a .Dq discovering interface. When the bridge has no address cache entry (either dynamic or static) for the destination address of a packet, the bridge will forward the packet to all member interfaces marked as .Dq discovering . This is the default for all interfaces added to a bridge. .It Cm -discover Ar interface Clear the .Dq discovering attribute on a member interface. For packets without the .Dq discovering attribute, the only packets forwarded on the interface are broadcast or multicast packets and packets for which the destination address is known to be on the interface's segment. .It Cm ipf Enable packet filtering with .Xr pfil 9 on the bridge. The current implementation passes all ARP and RARP packets through the bridge while filtering IP and IPv6 packets through the configured packet filter, such as .Xr npf 7 . Other packet types are blocked. .It Cm learn Ar interface Mark an interface as a .Dq learning interface. When a packet arrives on such an interface, the source address of the packet is entered into the address cache as being a destination address on the interface's segment. This is the default for all interfaces added to a bridge. .It Cm -learn Ar interface Clear the .Dq learning attribute on a member interface. .It Cm protect Ar interface Mark an interface as a .Dq protected interface. When a packet arrives on a .Dq protected interface and is being forwarded to another .Dq protected interface, the packet will be discarded. .It Cm -protect Ar interface Clear the .Dq protected attribute on a member interface. .It Cm static Ar interface address Add a static entry into the address cache pointing to .Ar interface . Static entries are never aged out of the cache or replaced, even if the address is seen on a different interface. .It Cm stp Ar interface Enable Spanning Tree protocol on .Ar interface . The .Xr bridge 4 driver has support for the IEEE 802.1D Spanning Tree protocol (STP). Spanning Tree is used to detect and remove loops in a network topology. .It Cm -stp Ar interface Disable Spanning Tree protocol on .Ar interface . This is the default for all interfaces added to a bridge. .It Cm maxage Ar seconds Set the time that a Spanning Tree protocol configuration is valid. The default is 20 seconds. The minimum is 1 second and the maximum is 255 seconds. .It Cm fwddelay Ar seconds Set the time that must pass before an interface begins forwarding packets when Spanning Tree is enabled. The default is 15 seconds. The minimum is 1 second and the maximum is 255 seconds. .It Cm hellotime Ar seconds Set the time between broadcasting of Spanning Tree protocol configuration messages. The default is 2 seconds. The minimum is 1 second and the maximum is 255 seconds. .It Cm priority Ar value Set the bridge priority for Spanning Tree. The default is 32768. Allowed numerical values range from 0 (highest priority) to 65535 (lowest priority). .It Cm ifpriority Ar interface Ar value Set the Spanning Tree priority of .Ar interface to .Ar value . The default is 128. The minimum is 0 and the maximum is 255. .It Cm ifpathcost Ar interface Ar value Set the Spanning Tree path cost of .Ar interface to .Ar value . The default is 55. The minimum is 0 and the maximum is 65535. .El .Sh EXAMPLES The following, when placed in the file .Pa /etc/ifconfig.bridge0 , will cause a bridge called .Sq bridge0 to be created, add the interfaces .Sq ray0 and .Sq fxp0 to the bridge, and then enable packet forwarding. Such a configuration could be used to implement a simple 802.11-to-Ethernet bridge (assuming the 802.11 interface is in ad-hoc mode). .Bd -literal -offset indent create !brconfig $int add ray0 add fxp0 up .Ed .Pp Consider a system with two 4-port Ethernet boards. The following placed in the file .Pa /etc/ifconfig.bridge0 will cause a bridge consisting of all 8 ports with Spanning Tree enabled to be created: .Bd -literal -offset indent create !brconfig $int \e add tlp0 stp tlp0 \e add tlp1 stp tlp1 \e add tlp2 stp tlp2 \e add tlp3 stp tlp3 \e add tlp4 stp tlp4 \e add tlp5 stp tlp5 \e add tlp6 stp tlp6 \e add tlp7 stp tlp7 \e up .Ed .Sh SEE ALSO .Xr bridge 4 , .Xr pf 4 , .Xr ifconfig.if 5 , .Xr npf 7 , .Xr ifconfig 8 , .Xr pfil 9 .Sh HISTORY The .Nm utility first appeared in .Nx 1.6 . .Sh AUTHORS The .Xr bridge 4 driver and .Nm utility were originally written by .An Jason L. Wright .Aq jason@thought.net as part of an undergraduate independent study at the University of North Carolina at Greensboro. .Pp This version of the .Nm utility was written from scratch by .An Jason R. Thorpe .Aq thorpej@wasabisystems.com .