DHCPD Client bad UDP checksum

English Network/Internet
1

Greetings!

On a openSuSE-11.3 (patches updated) dhcpd fills the logfiles with below messages:

dhcp Server (openSuSE-11.3):

Dec 11 11:32:38 GTW dhcpd: DHCPREQUEST for 192.168.1.108 from 00:16:3e:00:a0:08 via eth0
Dec 11 11:32:38 GTW dhcpd: DHCPACK on 192.168.1.108 to 00:16:3e:00:a0:08 via eth0
…

dhcp Client (openSuSE-11.3):

Dec 11 11:33:38 M8V dhcpcd[1942]: eth0: bad UDP checksum, ignoring
…

This goes for hours and spams up logfiles.

Any hints how to repair this?

2

Faulty network hardware?

3

NICs on client and server already changed, no difference.

4

Cable? Switch port?

5

Sorry, forgot to mention that this are virtual machienes.
Problem solved with disabling ip checksum:
ethtool -K eth0 tx off
in the if-up script.

6

Maybe installing some vmwaretools/xenservertools or something else (appropriate for the virtual environment you’re running) will solve the problem without disabling the ip checksum.

Best regards,
Greg

7

Sorry, I do not understand how I can solve this problem by using xen-tools.
Could you be more specific?

Thanks, Wolf

8

I don’t know what virtualization software You are using but in Citrix XenServer when You create a VM it is installed without xenserver tools. These sometimes provide better drivers for the virtual hardware of the VM (they work better with the hypervisor) and You have to install the xenserver tools manually. Usually the standard linux drivers work very nice with virtualization (unlike Windows) but still installing xenserver tools sometimes allows the VM to run more efficiently. So maybe there is some bug in your VM drivers because of which You have to disable the checksum and maybe after installing xenserver tools (if You don’t have them installed already) the problem will go away and You will be able to reenable the checksum checking.

This link tells You how to install xenserver tools on Citrix XenServer. Citrix Product Documentation Library
Of course if You’re using VMware or something else the tools are called differently and the install procedure will most likely be different but I can’t guide You on that as I have not so much experience with other virtualization software.

Best regards,
Greg

9

Thanks Greg.
I’m using XEN and will check the Critrix xenserver.

Wolf