Am 2016-05-23 um 12:50 schrieb Matthias Leopold: > Hi, > > i'm rather new to kvm. now i set up a centos 7 guest on a centos 6 kvm > host. > > when i try to use bridged networking in the centos7 guest this works for > the interface that uses eth1/br1 on the host. when i try to use a second > interface in the guest with eth0/br0 on the host this brings the host > interface down as soon as i do ip configuration in the guest (so it > seems). eth0 shall have the default route in host and guest. three other > centos 6 guests (not set up by me) use both interfaces in bridged mode > with no problems. > > both interfaces on the host are intel cards (e1000e). driver in the kvm > guest configuration is "virtio". > > dmesg on the kvm host (centos 6) says: > > device vnet9 entered promiscuous mode > br0: port 5(vnet9) entering forwarding state > device vnet10 entered promiscuous mode > br1: port 5(vnet10) entering forwarding state > vnet10: no IPv6 routers present > vnet9: no IPv6 routers present > kvm: 17778: cpu0 disabled perfctr wrmsr: 0xc2 data 0xffff > e1000e: eth0 NIC Link is Down > ... > > ethtool -k output differs in "rx-vlan-filter" (off for eth0) > centos 6 kernel is 2.6.32-573.22.1.el6.x86_64 > > what could be wrong? okay.... all this was caused by switch configuration in our network, no relation to kvm... bye matthias