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OK HOST AND GUEST can ping each other
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HOST
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bridge=br0
brctl addbr ${bridge}
ifconfig ${bridge} 192.168.0.1 up
ifconfig ${bridge} down
brctl delbr ${bridge}
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GUEST
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virt-manager
网络源：指定共享设备名称
网络名称：br0
设备型号：virtio or rtl8139 or e1000
ifconfig eth0 192.168.0.2 up
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then, can ping each other
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