Description of problem: I followed the guide at http://wiki.libvirt.org/page/Networking#Fedora.2FRHEL_Bridging Also set "net.ipv4.ip_forward = 1" on /etc/sysctl.conf, just to make sure. Also disabled iptables, ip6tables and selinux. And configured my guest as: <interface type='bridge'> <mac address='52:54:00:82:15:46'/> <source bridge='br0'/> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> When the guest is running, the vnet0 interface is created on the host: host# ifconfig br0 Link encap:Ethernet HWaddr FE:54:00:82:15:46 inet6 addr: fe80::a001:aeff:fe66:a2c2/64 Scope:Link inet6 addr: fe80::ac1d:64ff:febe:d90e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:766 errors:0 dropped:0 overruns:0 frame:0 TX packets:90 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:86647 (84.6 KiB) TX bytes:7704 (7.5 KiB) em1 Link encap:Ethernet HWaddr 00:26:18:45:E7:7E inet addr:172.16.174.4 Bcast:172.16.174.255 Mask:255.255.255.0 inet6 addr: fe80::226:18ff:fe45:e77e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:258729 errors:0 dropped:0 overruns:0 frame:0 TX packets:162207 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:26848443 (25.6 MiB) TX bytes:471785702 (449.9 MiB) Interrupt:40 Base address:0xe000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:65598 errors:0 dropped:0 overruns:0 frame:0 TX packets:65598 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:79288846 (75.6 MiB) TX bytes:79288846 (75.6 MiB) vnet0 Link encap:Ethernet HWaddr FE:54:00:82:15:46 UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b) But the guest is unable to get an IP from my LAN DHCP server. No communication even if a set a valid fixed IP on the guest, as 172.16.174.6. The guest is Windows 7 with virtio drivers. This was working on Fedora 14. Relevand lines from /var/log/messages: Nov 20 12:59:50 fortal kernel: [ 6012.081648] br0: port 1(vnet0) entering forwarding state Nov 20 12:59:50 fortal NetworkManager[1045]: <warn> /sys/devices/virtual/net/vnet0: couldn't determine device driver; ignoring... Version-Release number of selected component (if applicable): libvirt-0.9.6-2.fc16.x86_64 kernel-3.1.1-1.fc16.x86_64 iptables-1.4.12-2.fc16.x86_64 NetworkManager-0.9.1.90-5.git20110927.fc16.x86_64 initscripts-9.34-2.fc16.x86_64
Did you upgrade from a working f14 and it stopped working? In your case, are you bridging em1 to br0 (and the guest to br0) ? (because your lan is connected to em1)? --- Here is an example from my f15/f16 dualboot machine: # cat /etc/sysconfig/network-scripts/ifcfg-br0 DEVICE=br0 TYPE=Bridge BOOTPROTO=static ONBOOT=yes DELAY=0 IPADDR=192.168.0.10 NETWORK=192.168.0.0 NETMASK=255.255.255.0 GATEWAY=192.168.0.1 MTU=1500 DNS1=192.168.0.1 IPV6INIT=no USERCTL=no # cat /etc/sysconfig/network-scripts/ifcfg-p33p1 DEVICE=p33p1 HWADDR=FF:FF:FF:FF:FF:FF ONBOOT=yes BRIDGE=br0 After configuing these files, disable Network Manager (i do use static ip): # systemctl stop NetworkManager.service # systemctl disable NetworkManager.service And enable traditional network service: # systemctl enable network.service # systemctl start network.servce Now: # brctl show bridge name bridge id STP enabled interfaces br0 8000.14dae9299cf7 no p33p1 virbr0 8000.000000000000 yes With this setup, i set the guest to bridged using "host device em1 (bridge 'br0')" i virt-manager
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
From the output of ifconfig, it appears that you have not fully followed the directions for creating a bridge device and connecting it to a physical ethernet device: 1) The bridge device has no IP address, but the physical ethernet does have an IP address. If the bridge is properly configured according to the page you reference, the bridge device will have an IP address, and the physical ethernet adapter will not. 2) Since a Linux bridge device takes on the numerically *lowest* MAC address of all attached devices, and your br0 device shows that it has the same MAC address as vnet0 (which is much *higher* than the MAC address of the physical device em1), it is clear that the physical device has not been attached to the bridge. Please verify that your /etc/sysconfig/network-scripts/ifcfg-em1 and ifcfg-br0 are similar to those posted by Reartes Guillermo in Comment 1. If they are, and you are still experiencing the problem, feel free to re-open this bug report. In the meantime, I'm closing it as NOTABUG, since it appears to be a configuration problem (and if there is a bug, not a libvirt bug, since devices being configured outside of libvirt are obviously not correctly configured).
(In reply to comment #6) Laine, thank you for this observations. I'll have a look in my system again to make sure everything is correct.