Hi I don't know if it is a feature or a bug, but when I do a full clone of a kvm virtual machine by the WebUI, the mac address of the new machine is not the same than the source machine. When I read this https://pve.proxmox.com/wiki/Duplicate_Virtual_Machines I do understand that if you want a new mac address you must remove the NIC after the cloning and add a new one. I run the last proxmox version : root@htpc:~# apt list proxmox* pve* Listing... Done proxmox-ve/now 4.2-48 all [installed,local] pve-cluster/now 4.0-39 amd64 [installed,local] pve-container/now 1.0-62 all [installed,local] pve-firewall/now 2.0-25 amd64 [installed,local] pve-firmware/now 1.1-8 all [installed,local] pve-ha-manager/now 1.0-28 amd64 [installed,local] pve-kernel-4.4.6-1-pve/now 4.4.6-48 amd64 [installed,local] pve-libspice-server1/now 0.12.5-2 amd64 [installed,local] pve-manager/now 4.2-2 amd64 [installed,local] pve-qemu-kvm/now 2.5-14 amd64 [installed,local] When I do a backup and then I restore it to another VM ID, the mac address is the same, so I have an immediate workaround because I mainly use proxmox to virtualise SME Server and the Mac address is used in the configuration database to set the IP. Therefore if the mac change, you must reconfigure you vm before to use the network.