Beyond Linux® From Scratch (System V Edition) - Version 11.0

Chapter 15. Networking Programs

bridge-utils-1.7.1

Introduction to bridge-utils

The bridge-utils package contains a utility needed to create and manage bridge devices. This is useful in setting up networks for a hosted virtual machine (VM).

This package is known to build and work properly using an LFS-11.0 platform.

Package Information

bridge-utils Dependencies

Optional (to run tests)

Net-tools-2.10

User Notes: https://wiki.linuxfromscratch.org/blfs/wiki/bridge

Kernel Configuration

Enable the following options in the kernel configuration and recompile the kernel if necessary: 

[*] Networking support --->            [CONFIG_NET]
      Networking options --->
        <*/M> 802.1d Ethernet Bridging [CONFIG_BRIDGE]

Installation of bridge-utils

Install bridge-utils by running the following commands: 

autoconf                  &&
./configure --prefix=/usr &&
make

Testing the results requires running the six shell scripts in the tools/ directory. Two of the tests require two ethernet ports. Some tests will not preserve the current network configuration. See tests/README for details.

Now, as the root user: 

make install

Configuring bridge-utils

Configuration Information

To automate bridge creation and configuration, install the /lib/services/etc/bridge service script included in the blfs-bootscripts-20210826 package. 

make install-service-bridge
[Note]

Note

The bridge script depends on the commands /sbin/ifup and /sbin/ifdown and the service script ipv4-static from the LFS bootscripts dated January 27, 2012 or later.

The following configuration file will create a bridge device at boot time and attach the eth0 device to it. If more than one device is desired, use a space separated list of INTERFACE_COMPONENTS. This configuration is useful when planning to run a virtual machine such as kvm/qemu.

Other SERVICE combinations are possible, for example, SERVICES="bridge dhcp". In that case, the address parameters are not needed, but do not interfere if present. The bridge service may also be used alone, but will require additional subsequent configuration.

[Caution]

Caution

Do not run a parallel configuration for a device in the INTERFACE_COMPONENTS list. For instance, in the example below, do not configure /etc/sysconfig/ifconfig.eth0 to run at boot time. The command ifdown br0 followed by command ifup eth0 will work, but don't try to have both up at the same time. 

cat > /etc/sysconfig/ifconfig.br0 << "EOF"
ONBOOT=yes
IFACE=br0
VIRTINT=yes
SERVICE="bridge ipv4-static"  # Space separated
IP=192.168.1.32
GATEWAY=192.168.1.1
PREFIX=24
BROADCAST=192.168.1.255
CHECK_LINK=no                 # Don't check before bridge is created
STP=no                        # Spanning tree protocol, default no
INTERFACE_COMPONENTS="eth0"   # Add to IFACE, space separated devices
IP_FORWARD=true
EOF

All addresses should be changed to meet your circumstance.

Contents

Installed Program: brctl
Installed Libraries: None
Installed Directories: None

Short Descriptions

brctl

is a program used to set up, maintain, and inspect the ethernet bridge configuration in the linux kernel

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