I got. Thank you! From: yue [mailto:libvirt@163.com] Sent: Thursday, April 18, 2013 4:58 PM To: Wangkai (Kevin,C) Cc: libvirt-users(a)redhat.com Subject: Re:[libvirt-users] How can I define a network using an exist host bridge Nat network can not share bridge with others. 在 2013-04-18 10:35:51，"Wangkai (Kevin,C)" <wangkai86(a)huawei.com&gt; 写道： Hi all, When I defined a network use the host bridge “virbr1” an error occurred : “libvir: error : Unable to create bridge virbr1: File exists” But how can I define this network use the host bridge “virbr1” ? <network> <name>def1</name> <bridge name='virbr1'/> <forward mode='nat'> <interface dev='eth0'/> </forward> </network> Thanks, Kevin