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Ip Checksum offload in Vmware VMs.

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Hello Experts. My Windows File server is so slow and it is Virtualized on Vmware ESXi 5.5. I capture some packets via Wireshark and it show me "Ip Checksum offload". How can I solve it?link text

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I attached two photos and I'm thankful if you help me.

Thank you.

asked 09 May '15, 07:42

hack3rcon's gravatar image

hack3rcon
11778
accept rate: 0%


One Answer:

2

You really should not solve this!

Because Wireshark told you something different.

Wireshark has seen a wrong IP Checksum (0x0000) and not (0x6460). So far so good. But the main cause for this behaviour is the feature Checksum offload and this fact is Wireshark telling you.

With this feature enabled network interface makes the checksum calculations and not the CPU. So if the checksum calculation is donne in the interface, Wireshark has no chance to see the Checksums.

My recommendation for your analysis is to disable the coloring rule with (fcs_bad).

And this has nothing to do with your slow connections. The root cause of your slow connection problem is a different. But this root cause I really can´t tell you with nothing more than this screenshots.

If you want further assistance you should upload a trace on cloudshark.

answered 14 May '15, 15:50

Christian_R's gravatar image

Christian_R
1.8k2625
accept rate: 16%

edited 14 May '15, 15:52