Troubleshoot a MACVTAP network in Kvm/virt-manager

Http://askubuntu.com/questions/377413/how-to-troubleshoot-a-macvtap-network-in-kvm-virt-manager

2 down vote favorite 1

I have a virtual machine running under QEMU-KVM, on a 13.10 host. I am using Virt-manager to define the machine, and I have added a virtual NIC, using the new Macvtap driver. I have the following definition: <interface type= ' direct ' > <mac address= ' 52:54:00:1f:dd:c4 ',/> <source dev= ' eth0 ' mode= ' Bridge '/> <model type= ' virtio '/> <address ' type= ' PCI ' domain= ' 0x0000 ' ' bus= ', 0x00 ' slot= ' ' 0x03 ' function= ' 0x0 '/> </interface> On the host machine, I can and the tap interface is created: $ip link 5:macvtap0@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> MTU 1500 Qdisc pfifo_fast State UNKNOWN mode Defau LT qlen link/ether 52:54:00:1f:dd:c4 brd ff:ff:ff:ff:ff:ff $ls/dev/tap5/dev/tap5 But in the virtual machine, interface eth0 are unable to access the network. DHCP fails. Static configuration obviously works, but then I cannot ping anything. I have no iptables rules, neither on the host, nor in the virtual machine. So, how can I troubleshoot this problem?

1 down vote accepted

I have same problem with the Ubuntu 13.10, I also update to 14.04 development the to try branch but the not still. I don't know a good way debug, for my problem, I found eth0 does not enter promiscuous mode, I can Device Eth0 entered promiscuous mode in DMESG output. So I force eth0 into promiscuous mode, the problem then disappears. This is what I did:force eth0 into promiscuous mode:sudo ifconfig eth0 Promisc with Virt-manager to start the VM ifconfig -A and ping outside to, whether it works for you. I do not know why Libvirt does not put eth0 into promiscuous mode, maybe a bug of it.