Bug 618558 - UDP checksum offload breaks DHCP on virtual machines
UDP checksum offload breaks DHCP on virtual machines
Status: CLOSED DUPLICATE of bug 605555
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
low Severity urgent
: rc
: ---
Assigned To: Michael S. Tsirkin
Red Hat Kernel QE team
: Reopened, RHELNAK
Depends On:
Blocks: 580953
  Show dependency treegraph
Reported: 2010-07-27 05:23 EDT by Neil Wilson
Modified: 2013-01-09 17:56 EST (History)
1 user (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2010-08-04 17:50:39 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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External Trackers
Tracker ID Priority Status Summary Last Updated
Launchpad 610391 None None None Never

  None (edit)
Description Neil Wilson 2010-07-27 05:23:17 EDT
Description of problem:

While running an Ubuntu Lucid virtual server under kvm on RHEL6, the DHCP system reports 'bad udp checksum' in response to DHCP offer packets coming from the libvirt launched dnsmasq process on the Host. Comparing RHEL5 to RHEL6 show that tx checksumming is switched on across the 'vnet' interfaces. 

Version-Release number of selected component (if applicable):

kernel.x86_64 2.6.32-44.1.el6 @anaconda-RedHatEnterpriseLinux6-201004141252.x86_64/6.0

How reproducible:

Setup a virtual network handing out DHCP addresses and run a virtual machine running dhclient3. If you run the dhclient3 in the console, you will see 'bad udp checksum in 5 packets' errors. tcpdump shows that the DHCP offer packet are reaching the virtual machine.

Steps to Reproduce:
Actual results:

'bad udp checksum in 5 packets'

Expected results:

virtual machine picks up the ip address as normal.

Additional info:

Comment 2 Neil Wilson 2010-07-27 05:56:41 EDT
Ubuntu bug:

Comment 3 RHEL Product and Program Management 2010-07-27 05:58:06 EDT
This issue has been proposed when we are only considering blocker
issues in the current Red Hat Enterprise Linux release.

** If you would still like this issue considered for the current
release, ask your support representative to file as a blocker on
your behalf. Otherwise ask that it be considered for the next
Red Hat Enterprise Linux release. **
Comment 4 Dor Laor 2010-07-28 08:53:58 EDT
We solved that using netfilter, Michael ,please find the bug number to point to and close this bug
Comment 5 Michael S. Tsirkin 2010-07-28 09:55:57 EDT

*** This bug has been marked as a duplicate of bug 605555 ***
Comment 6 Neil Wilson 2010-07-28 10:39:03 EDT
I can't see that bug. What is the fix?
Comment 7 Neil Wilson 2010-07-29 06:31:47 EDT
Verified the bug with libvirt-0.8.1-15.el6.x86_64, kernel-2.6.32-52.el6.x86_64 and iptables-1.4.7-3.el6.x86_64, and PASSED
Comment 8 Michael S. Tsirkin 2010-08-03 10:56:27 EDT
Change to verified?
Comment 9 Dor Laor 2010-08-04 17:50:39 EDT

*** This bug has been marked as a duplicate of bug 605555 ***

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