Windows update KB5053603 on Windows Server 2022 issue with Network Load Balancer

Question

We have a Windows Network Load Balancer servicing a web application that runs on three nodes (Web1, Web2, Web3). After Installing Windows update KB5053603 on all nodes, the web app stopped working (clients can't access it). The web app has been running for months without any issues and no changes have been made.

When accessing the web app directly on the hosts individual IP addresses, the application loads and responds as normal. This confirms the web app itself is not the problem.

Digging a little deeper into the issue looks like the TCP packets between the NLB and the client have some sort of issue, and the client & server continue to re-send ACK packets. The re-transmission is both ways (client and server) and looks like after the initial handshake, the client sends a hello packet containing the SNI using TLS v1.3, but that packet is not reaching the server and both devices (client and server) start re-transmitting packets.

All server nodes are converged in the NLB, have a valid SSL certificate, and have TLS v1.3 is enabled.

Not sure how to further troubleshoot this issue. Any help would be appreciated.

Regards,

Answer 1

Hello,

Thank you for posting in Q&A forum.

First, you could try uninstalling the update and see if that resolves the issue. To do this, go to Settings > Update & Security > Windows Update > View update history > Uninstall updates. Find the update in question and click Uninstall.

If you are sure that the patch caused the problem, I suggest you go to Microsoft's Feedback Center to report the problem, which can help fix the problem in subsequent updates. You can press Win+F to open the Feedback Center to report the problem. You can also visit the following webpage to report the problem:

https://support.microsoft.com/en-us/windows/send-feedback-to-microsoft-with-the-feedback-hub-app-f59187f8-8739-22d6-ba93-f66612949332

I hope the information above is helpful.

Best regards

Zunhui

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