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Is there a way to disable the piggybacking of TCP ACKs?

Anonymous
2024-07-31T12:37:53+00:00

Is there a way, in Windows 10 and/or Windows 11, to prevent the workstation from using a normal TCP segment (one which bears stream data) from ACKing previously received stream data from the other end? Essentially, I want all ACKs to be standalone ACKs (which would typically result in an IP datagram of 40-80 bytes in length depending on the size of the TCP header and assuming a standard IP header length of 20 bytes)? The reason I ask is because I've run into a scenario wherein a workstation is receiving an MSS of 1261 bytes during 3-way handshake, it is generating a 1301 byte IP packet (which is the IP MTU of an upstream tunnel), but a TCP optimization feature further upstream is increasing the size of the TCP header by adding SACK info and is causing the IP datagram to balloon above the IP MTU. The workstation is setting the df-bit on the IP datagram and causing the router to drop the packet and send an ICMP response back to the workstation. I have a few options to consider. One is to adjust the MSS down by 40 more bytes to account for the worst-case scenario that the TCP header goes to 60 bytes. Another is to investigate tweaks to the TCP optimization feature. Another is to get the workstation to stop setting the df-bit. Another is to change the ACK behavior of the workstation to prevent it from piggybacking the ACK on a large (usually full-sized) TCP segment.

Windows for business Windows Client for IT Pros Networking Other

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  1. Anonymous
    2024-08-01T07:49:00+00:00

    Hello,

    Thank you for posting in Microsoft Community forum.

    Based on your description, this issue is beyond the scope of our support.

    To be able to get a quick and effective handling of your issue, I recommend that you repost your question in the Q&A forum, where there will be a dedicated engineer to give you a professional and effective reply.

    Here is the link for Q&A forum.

    Questions - Microsoft Q&A

    Click the "Ask a Question" button in the upper right corner to post your question and select tags related to your products.

    I hope the information above is helpful.

    If you have any questions or concerns, please feel free to let us know.

    

    Regards,

    Jill Zhou

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