Packet Loss after Windows Updates

[KKlau]

Hi *.

after recent Windows Updates, I experience about 20% packet loss of all network connection through a Windows Server 2008 R2 Hyper-V vm running on a Windows Server 2016 TP5 host. Were there any changes to the Intel drivers recently?

/Klaus

[idata]

Hi Klaus,

Thank you for the post. Please provide more information for better checking:1) What is the network adapter model?2) What is the brand and model of your server system?3) What is the network adapter driver version for the host and virtual machine? Thanks,wb

[KKlau]

The adapter is an on-board i350-4-port adapter on a Supermicro X10SRH-CLN4F board.

Driver is 12.12.50.6 and got installed with the operating system.

The issue occured after patching Windows Server 2016 TP5 to the latest version.

The hard part is to find out whether the nic or the operating system (of the host or the vm) is responsible for the behaviour. The packet loss seems to be caused by windows sending packets to all network adapters when in fact only one should be used.

Net config is 192.168.1.10/24 gate 192.168.1.1 for nic1 and 10.168.1.10/8 for nic2. there is no default gateway defined for nic2. All traffic to 192.168.1.1 is affected as about 20% of the packets seem to be sent out to nic2. if i disable nic2, all packet loss is gone. if i enable nic2, packet loss occurs again. For me it looks like some kind of weird nic teaming.

The exact same configuration worked for more than 5 month before the windows updates.

/Klaus

[idata]

Hi Klaus,

As this is on-board nic on Supermicro system, have you tried contacting Supermicro for support? Thanks,wb

[KKlau]

In fact, I haven't , as i am pretty sure it is not hardware related.

It looks like something is telling the system "use both nics to contact target even if one has no corresponding network configured" - so for me is either the nic driver or overlying network components.

So do you know whether something has changed in the nic drivers provided to Microsoft recently?

/Klaus

[idata]

Hi Klaus,

Thank you for the information. This is onboard NIC on Supermicro system, it is recommended to obtain with system vendor the customized driver that suits the onboard NIC for your system. Please do let me know if issue persist with the driver from Supermicro. Thanks,wb

[idata]

Hi Klaus,

Just want to follow up if you have checked with Supermicro* for the driver and if issue persist.Thanks.wb

[KKlau]

Hi,

yes, I have checked for drivers and there is version 21 available (currently using 20.6). However, I did not have the time to install yet.

/Klaus

[idata]

Hi Klaus,

Thank you for the update. Please try using the driver from Supermicro* and feel free to update the result. rgds,wb

[idata]

Hi Klaus,

Any update for the test result?rgds,wb

[KKlau]

Hi,

as I did not have the time to test everything thouroughly, I did two things at a time, so unfortunately, I cannot say what did fix the problem. I have reinstalled the OS from scratch (it was just a Hyper-V host after all) and installed the latest drivers from Supermicro, enabled Hyper-V role and voila.... everything back to normal.

However, I have not given up on this. When I have more time, I will start to investigate again.

Best Regards,

Klaus

[idata]

Hi Klaus,

Thanks for the update and I am glad you manage to make it work. Please feel free to share your investigation result when you have the time.Thank you.rgds,wb