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  • TCP checksum offload errors

    Hi,
    I had a lot of TCP checksum offload errors in the network (saw it in wireshark).
    The OS is windows 2008 web on ESX.

    I disabled the following configuration due to VMware forums recomendation:
    IPv4 Large sent offload
    IPv4 Checksum Offload
    TCP Checksum Offload (IPv4)
    UDP Checksum Offload (IPv4)

    The results as I see them:
    1. RDP / Network works faster
    2. no tcp checksum offload errors.

    Do you recognize this issue ?

    Does Microsoft has a fix for this issue ?

    Thanks,
    Michael

  • #2
    Re: TCP checksum offload errors

    Do you have the latest drivers for your network cards (and firmware if appropriate)?

    What errors did you see specifically? Don't forget that Wireshark attempts to do a checksum before the information gets to the card so will show a checksum error by default if the offload is being performed. (not sure I could have made that sentence longer...!)
    cheers
    Andy

    Please read this before you post:


    Quis custodiet ipsos custodes?

    Comment


    • #3
      Re: TCP checksum offload errors

      Hi,

      I had a lot of SQL connection timeouts in the application.
      That is why I installed wireshark in the first place.

      Meanwhile, I do not get these SQL connection timeouts.

      The servers are VMs on ESX.
      VMtools are installed.

      Michael

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      • #4
        Re: TCP checksum offload errors

        Is IPv6 enabled? I have had issues with ticketing software that uses SQL server that was caused due to IPv6. May be worth disabling and rebooting the server.

        Comment


        • #5
          Re: TCP checksum offload errors

          These are not real checksum errors, just false reporting by Wireshark.

          http://wiki.wireshark.org/TCP_Checksum_Verification

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          • #6
            Re: TCP checksum offload errors

            Hmm, I think you can argue it isn't false reporting (as such), just that the information was changed after Wireshark read it (like my post said! )
            cheers
            Andy

            Please read this before you post:


            Quis custodiet ipsos custodes?

            Comment

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