[openstack-dev] [Neutron] virtual machine can not get DHCP lease due packet has no checksum

Rick Jones rick.jones2 at hp.com
Tue Jun 2 16:33:11 UTC 2015


On 06/02/2015 12:32 AM, Ian Wells wrote:
> The fix should work fine.  It is technically a workaround for the way
> checksums work in virtualised systems, and the unfortunate fact that
> some DHCP clients check checksums on packets where the hardware has
> checksum offload enabled.  (This doesn't work due to an optimisation in
> the way QEMU treats packet checksums.  You'll see the problem if your
> machine is running the VM on the same host as its DHCP server and the VM
> has a vulnerable client.)

Is that specific to DHCP clients, or does this issue affect UDP traffic 
in general?

rick jones



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