Hi everyone,
I use Windows Server 2008 R2 SP1, and I used Network Monitor 3.4 to capture packages and found sometimes the server recevied some tcp package with bad checksum from client and the client will retransmit the package without bad checksum,
but my application like iis will receive the data in the package with bad checksum.
I try some servers with the same OS, and I found only if the servers use Broadcom BCM5708C NetXtreme II GigE network adapter have this problem.
Does anyone have the same problem? and how to resolve it?
Thank you.
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I try reinstall the network adapter driver, when finish the install application could receive currect package but after seconds application received wrong package again.
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Hi,
The problem may cause by your NIC settings. Please go into the properties of your NIC driver and disable TCP Checksum Offload.
Turn off all network card offload functionality (disable TCP Checksum Offload):
Right-Click My Computer > Properties >
Hardware Tab > Device Manager.
Click Network Adapters > right-click Broadcom BCM5708S NetXtreme II GigE
> Properties.
Click Advanced Tab > Property: Checksum Offload > Value:
None.
Advanced Tab > Property: Large Send Offload > Value:
Disable.
To resolve this issue, you can use individual network adapters instead of this Broadcom Network adapter. And you also need to contact the NIC vendor support for further investigation. Your understanding is highly appreciated.
A bug report of Broadcom BCM5708C NetXtreme II GigE listed in Windows Server 2008 feedback center.
Broadcom BCM5708C NetXtreme II GigE causes TCP Checksum failures in VM

http://connect.microsoft.com/WindowsServerFeedback/feedback/details/329074/broadcom-bcm5708c-netxtreme-ii-gige-causes-tcp-checksum-failures-in-vm

Best Regards,
AidenAiden Cao
TechNet Community Support

Need to support users over the internet? click here try our remote control online beta

Hi,
The problem may cause by your NIC settings. Please go into the properties of your NIC driver and disable TCP Checksum Offload.
Turn off all network card offload functionality (disable TCP Checksum Offload):
Right-Click My Computer > Properties >
Hardware Tab > Device Manager.
Click Network Adapters > right-click Broadcom BCM5708S NetXtreme II GigE
> Properties.
Click Advanced Tab > Property: Checksum Offload > Value:
None.
Advanced Tab > Property: Large Send Offload > Value:
Disable.
To resolve this issue, you can use individual network adapters instead of this Broadcom Network adapter. And you also need to contact the NIC vendor support for further investigation. Your understanding is highly appreciated.
A bug report of Broadcom BCM5708C NetXtreme II GigE listed in Windows Server 2008 feedback center.
Broadcom BCM5708C NetXtreme II GigE causes TCP Checksum failures in VM

http://connect.microsoft.com/WindowsServerFeedback/feedback/details/329074/broadcom-bcm5708c-netxtreme-ii-gige-causes-tcp-checksum-failures-in-vm

Best Regards,
AidenAiden Cao
TechNet Community Support

There is an amazing pack of free network admin tools. click here to download it