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Windows 7 TCPIP tuning (Sack and TCP1323 options)

    Question

  • In windows 7 ultimate, i try to disable SACK option et TCP1323 option using regedit like this

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]

    "Tcp1323Opts"=dword:00000000

    "SackOpts"=dword:00000000

    It doesn't work

    I have tried hotfix found at http://support.microsoft.com/kb/2525390/en-us (install and reboot), it doesn't work too.
    When I watch first TCP frame using wireshark, I see in TCP option:
     - SACK Permitted (I want not permitted)
     - Windows scale:2 (i want 0)
    How to solve this problem?

    Monday, June 06, 2011 3:41 PM

Answers

  • Hi,

    First, please make sure the following situations are true.

    The TCP Offloading feature is enabled.

    You install a TCP offloading capable network adapter on the computer and keep it active.

    If the situations are true, then the SACK option will be automatically disabled. If not, the option cannot be disabled manually.

    The Tcp1323 is not disabled manually as well.

    Thanks for understanding.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. ”
    Wednesday, June 08, 2011 10:03 AM

All replies

  • Hi,

    First, please make sure the following situations are true.

    The TCP Offloading feature is enabled.

    You install a TCP offloading capable network adapter on the computer and keep it active.

    If the situations are true, then the SACK option will be automatically disabled. If not, the option cannot be disabled manually.

    The Tcp1323 is not disabled manually as well.

    Thanks for understanding.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. ”
    Wednesday, June 08, 2011 10:03 AM
  • Hi,

     

      Thanks for your response.

      It seems that my network adapter doesn't support TCP Offloading.

      Why this features have been removed?

      Does microsoft plan to re-add this features in short term?

     

    Wednesday, June 08, 2011 11:39 AM
  • Hi,

    If you find have any inconveniences or suggestions, please submit your feedback to our Product Feedback Team : http://mymfe.microsoft.com/Windows%20%207/Feedback.aspx?formID=195. Our development team will find it.

    Thanks for your understanding.


    Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. ”
    Thursday, June 09, 2011 1:55 AM