I have over 20 guests running on a particular host and the three longest running ones are missing the network device information in their XML description: <interface type='network'> <mac address='54:52:10::f2:c5'/> <source network='local'/> </interface> Compared to the others which have: <interface type='network'> <mac address='54:52:d1:32:0a:a1'/> <source network='local'/> <target dev='vnet13'/> </interface> This is problematic as I wanted to use domifstat on the domains. Using the packet counts shown via ifconfig on the host, I was able to determine what the vnet interface should be, but passing that to domifstat doesn't work: $ virsh domifstat maki221 vnet13 Connecting to uri: qemu:///system error: Failed to get interface stats guest19 vnet13 error: invalid argument in invalid path, 'vnet13' is not a known interface How did this happen? Is there a way I can get libvirt to know about the interfaces? And the guest OS's network connections work fine. Thanks! .:. jeremy