Hi all, I am using libvirt to manage VM on my system; after creating a VM (default no NICs are present in the configuration) you can add any number of interfaces to it (as long as they exist on the host). To do that, I edit the configuration xlm: vmXml = self.domain.XMLDesc() root = ET.fromstring(vmXml) devices = root.find('./devices') intf = ET.SubElement(devices,'interface') intf.set('type', 'bridge') src = ET.SubElement(intf,'source') src.set('bridge', bIntf) model = ET.SubElement(intf,'model') model.set('type', 'e1000') xml = ET.tostring(root) self.conn.defineXML(xml) Now the problem I have is that the MAC addresses are auto-generated and because of this there is no way to predict which interface number the newly added interface will map to, on the VM. Ideally, the first added interface is mapped to eth0/0, the second one eth0/1...etc. Since the mappings depend on the MAC addresses I figured that is the part I need to have control over. Any ideas? Thanks, Andrei -- The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you receive this in error please contact the sender and delete the material from any computer immediately. It is the policy of Klas Limited to disavow the sending of offensive material and should you consider that the material contained in the message is offensive you should contact the sender immediately and also your I.T. Manager. Klas Telecom Inc., a Virginia Corporation with offices at 1101 30th St. NW, Washington, DC 20007. Klas Limited (Company Number 163303) trading as Klas Telecom, an Irish Limited Liability Company, with its registered office at Fourth Floor, One Kilmainham Square, Inchicore Road, Kilmainham, Dublin 8, Ireland.