10.2. Bridged networking with libvirt
If your system was using a Xen bridge, it is recommended to disable the default Xen network bridge by editing
/etc/xen/xend-config.sxp and changing the line:
NetworkManager does not support bridging. Running NetworkManager will overwrite any manual bridge configuration. Because of this, NetworkManager should be disabled in order to use networking via the network scripts (located in the
# chkconfig NetworkManager off # chkconfig network on # service NetworkManager stop # service network start
NM_CONTROLLED=no" to the
ifcfg-*scripts used in the examples. If you do not either set this parameter or disable NetworkManager entirely, any bridge configuration will be overwritten and lost when NetworkManager next starts.
Create or edit the following two network configuration files. This step can be repeated (with different names) for additional network bridges.
# cd /etc/sysconfig/network-scripts
ifcfg-eth0defines the physical network interface which is set as part of a bridge:
DEVICE=eth0 # change the hardware address to match the hardware address your NIC uses HWADDR=00:16:76:D6:C9:45 ONBOOT=yes BRIDGE=br0
MTUvariable to the end of the configuration file.
ifcfg-br0or similar. The
br0is the name of the bridge; this name can be anything as long as the name of the file is the same as the DEVICE parameter.
DEVICE=br0 TYPE=Bridge BOOTPROTO=dhcp ONBOOT=yes DELAY=0
ifcfg-br0file). Network access will not function as expected if IP address details are configured on the physical interface that twehe bridge is connected to.
TYPE=Bridge, is case-sensitive. It must have uppercase 'B' and lower case 'ridge'.
# service network restart
iptablesto allow all traffic to be forwarded across the bridge.
# iptables -I FORWARD -m physdev --physdev-is-bridged -j ACCEPT # service iptables save # service iptables restart
/etc/sysctl.confappend the following lines:
net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0
# sysctl -p /etc/sysctl.conf
# service libvirtd reload
# brctl show bridge name bridge id STP enabled interfaces virbr0 8000.000000000000 yes br0 8000.000e0cb30550 no eth0
virbr0bridge. Do not attempt to attach a physical device to
virbr0bridge is only for Network Address Translation (NAT) connectivity.