Linux Ethernet Bridging - Nov 2009 - [Bridge] [Bugme-new] [Bug 14586] New: bridge on bonding interface: DHCP replies don't get through

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On Wed, 11 Nov 2009 14:28:00 GMT
bugzilla-daemon at bugzilla.kernel.org wrote:
> http://bugzilla.kernel.org/show_bug.cgi?id=14586
> 
>            Summary: bridge on bonding interface: DHCP replies don't get
>                     through
>            Product: Networking
>            Version: 2.5
>     Kernel Version: 2.6.31.5
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: Other
>         AssignedTo: acme at ghostprotocols.net
>         ReportedBy: harald.dunkel at t-online.de
>         Regression: No
> 
> 
> I would like to run a bridge for kvm on a bonding interface (4 * 1Gbit,
Intel
> e1000e). Problem: The DHCPDISCOVER packets sent by the guest show up on my
dhcp
> server as expected, but the DHCPOFFER sent as a reply doesn't reach the
guest
> behind the bridge.
> 
> Using tcpdump on host and guest I can see the DHCPOFFER on the bond0 and
br0
> interface, but it never shows up on vnet0 or on the guest's eth0.
> 
> If I drop the bonding interface and use the host's eth2 for the bridge
instead,
> then there is no such problem.
> 
> Kernel on host and guest is 2.6.31.5. Attached you can find more
information
> about my setup. 
> 
> I had sent this information to the linux kvm mailing list before, but
consensus
> was that this is a bridging problem. See
> 
>     http://www.spinics.net/lists/kvm/msg25153.html
> 
> There was no reply on the linux bridge mailing list, see 
> 
>    
>
https://lists.linux-foundation.org/pipermail/bridge/2009-November/006749.html

> 
> I would like to run a bridge for kvm on a bonding interface (4 * 1Gbit,
Intel
> e1000e). Problem: The DHCPDISCOVER packets sent by the guest show up on my
dhcp
> server as expected, but the DHCPOFFER sent as a reply doesn't reach the
guest
> behind the bridge.
> 
> Using tcpdump on host and guest I can see the DHCPOFFER on the bond0 and
br0
> interface, but it never shows up on vnet0 or on the guest's eth0.
> 
> If I drop the bonding interface and use the host's eth2 for the bridge
instead,
> then there is no such problem.
> 
> Kernel on host and guest is 2.6.31.5. Attached you can find more
information
> about my setup. 
> 
What is the configuration?
# brctl showstp virbr0
# brctl showmacs virbr0

Is dhclient being run on the bridge interface?
# cat /proc/net/ptype

# cat /proc/net/bonding/bond0


How is bond and bridge configured? Are bonding bridges (wrong)
or bridging bonded interfaces?

Are all links up?

Since this is the initial packet it will have to be flood forwarded by
the bridge, is there any iptables/netfilter rule that might be blocking
packets?