mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-25 11:37:56 +00:00
79 lines
1.6 KiB
Groff
79 lines
1.6 KiB
Groff
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd Sep 28, 1998
|
|
.Dt BRIDGE 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm bridge
|
|
.Nd Bridging support
|
|
.Sh DESCRIPTION
|
|
Starting from version 2.2.8, FreeBSD supports bridging on ethernet-type
|
|
interfaces. This is achieved using the following option
|
|
.Bd -literal
|
|
options BRIDGE
|
|
.Ed
|
|
|
|
in the kernel config file, and is controlled by two
|
|
.Nm sysctl
|
|
variables:
|
|
.Bd -literal
|
|
net.link.ether.bridge
|
|
.Ed
|
|
|
|
Set to 1 to enable bridging, set to 0 to disable it
|
|
.Bd -literal
|
|
net.link.ether.bridge_ipfw
|
|
.Ed
|
|
|
|
Set to 1 to enable
|
|
.Nm ipfw
|
|
filtering on bridged packets. Note that
|
|
.Nm ipfw
|
|
rules only apply
|
|
to IP packets. Non-IP packets are subject to the default
|
|
.Nm ipfw
|
|
rule
|
|
.Pq number 65535
|
|
which must be an
|
|
.Ar allow
|
|
rule if we want ARP and other non-IP packets to flow through the
|
|
bridge.
|
|
|
|
|
|
.Sh BUGS
|
|
.Pp
|
|
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.
|
|
.Pp
|
|
With bridging active, interfaces are in promiscuous mode,
|
|
thus causing some load on the system to receive and filter
|
|
out undesired traffic.
|
|
.Pp
|
|
Extended functionality to enable bridging selectively on clusters
|
|
of interfaces is still in the works.
|
|
.Pp
|
|
Not all interface support bridging -- at the moment it works for
|
|
.Dq ed ,
|
|
.Dq de ,
|
|
.Dq ep ,
|
|
.Dq fe ,
|
|
.Dq fxp ,
|
|
.Dq lnc ,
|
|
.Dq mx ,
|
|
.Dq tx ,
|
|
and
|
|
.Dq xl
|
|
interfaces.
|
|
.Sh SEE ALSO
|
|
.Xr ip 4 ,
|
|
.Xr ipfw 8 ,
|
|
.Xr sysctl 8 .
|
|
.Sh HISTORY
|
|
.Nm
|
|
bridging was introduced in FreeBSD 2.2.8
|
|
by
|
|
.An Luigi Rizzo Aq luigi@iet.unipi.it .
|