###########Bridge方式使物理网段与VM在相同网段中###################   

br0: Configure Bridging for eth0

Edit /etc/sysconfig/network-scripts/ifcfg-eth0, enter:

# vi /etc/sysconfig/network-scripts/ifcfg-eth0

Update it as follows:

DEVICE=eth0

3ONBOOT=yes

ETHTOOL_OPTS="autoneg off speed 100 duplex full"

BRIDGE=br0

HWADDR=b8:ac:6f:65:31:e5

Save and close the file. Create /etc/sysconfig/network-scripts/ifcfg-br0, enter:

# vi /etc/sysconfig/network-scripts/ifcfg-br0

Update it as follows (note options are case sensitive i.e. Bridge and bridge are two different options)

DEVICE=br0

TYPE=Bridge

BOOTPROTO=static

ONBOOT=yes

IPADDR=10.10.21.70

NETMASK=255.255.255.192

DELAY=0

Save and close the file. Finally, create static routing file /etc/sysconfig/network-scripts/route-br0, enter :

# vi /etc/sysconfig/network-scripts/route-br0

Edit it as follows:

10.0.0.0/8 via 10.10.21.122 dev br0

Save and close the file. Delete old /etc/sysconfig/network-scripts/route-eth0 (if exists):

# rm /etc/sysconfig/network-scripts/route-eth0

service network restart

############################################################################

NAT方式IP网络转换，将VM 192.168.1.0/24网段进行转换，使虚拟机能够上网，但外网无法访问虚拟机

参考文档：

http://segmentfault.com/blog/koy/1190000000644069

http://www.linuxidc.com/Linux/2012-05/61445.htm

[root@oc1575550074 networks]# cd  /etc/libvirt/qemu/networks

[root@oc1575550074 networks]# scp default.xml   mynat.xml

[root@oc1575550074 networks]# cat mynat.xml      修改mynat 网段至192.168.1.0/24

<network>

  <name>mynat</name>

  <uuid>504730bc-0a59-4fb7-a4a7-9b779fa4bf79</uuid>

  <forward mode=‘nat‘/>

  <bridge name=‘br0‘ stp=‘on‘ delay=‘0‘ />

  <mac address=‘52:54:00:FD:BE:C8‘/>

  <ip address=‘192.168.1.1‘ netmask=‘255.255.255.0‘>

    <dhcp>

      <range start=‘192.168.1.2‘ end=‘192.168.1.254‘ />

    </dhcp>

  </ip>

</network>

[root@oc1575550074 networks]# virsh net-define    mynat.xml 

Network mynat defined from mynat.xml

[root@oc1575550074 networks]# virsh net-autostart  mynat

Network mynat marked as autostarted

[root@oc1575550074 networks]#  virsh net-start mynat

[root@oc1575550074 networks]# brctl show 

bridge name bridge id STP enabled interfaces

br0 8000.525400fdbec8 yes           br0-nic

br1 8000.000000000000     no

pan0 8000.000000000000     no

virbr0 8000.525400fdbec9 yes           virbr0-nic

[root@oc1575550074 networks]# 

本文出自 “Devops” 博客，谢绝转载！

virt-manager bridge 网桥设置