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don't fragment bit

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  • don't fragment bit

    hi all,

    I would like to know what is the default behaviour on windows machine regarding DF bit.

    is it set or not !?


  • #2
    Re: don't fragment bit

    Right now I have about 13 different DF abbreviations in my head. Please extrapolate exactly what DF you are referring to.

    1 1 was a racehorse.
    2 2 was 1 2.
    1 1 1 1 race 1 day,
    2 2 1 1 2


    • #3
      Re: don't fragment bit

      The default, as far as I know, is for the Don't Fragment bit to NOT be set. You can easily determine this by pinging another host using a size too large for the MTU of the physical medium in use. For instance; pinging another host on your LAN using a size of 1600 on an Ethernet network. If the DF flag were set this would not work.

      You can also see this in a network capture, using something like Wireshark or the like. You'll see that the MF flag (More fragments follow this fragment) is set when the ICMP Echo Request message size exceeds the MTU of the physical medium.