How to set MTU size to 100 on Windows 10

liujia 6 Reputation points
2021-09-01T09:22:58.307+00:00

I met a problem, a hosting Dell system(Product:"0K8Y0N". Installed Windows 10 or Windows Server 2019 to test) with Intel I210 gigabit network adapter can not revice/process Ethernet frame which bigger than 126 bytes. For example, ping ip-address -l 84 is okay, but ping ip-address -l 85 is timeout. And I can not RDP to Dell system, because TLS connection package is bigger than 126 bytes too.

I tried to setup a proxy server which installed Debian, set mtu to 112 on Debian. Then I can RDP to Dell system via Debian's SSH tunnel.

Can I set MTU size to 112 for Windows 10(Windows Server 2019)? I tried, but failed. 

C:\Windows\system32>netsh interface ipv4 set subinterface "Ethernet" mtu=352
Ok.


C:\Windows\system32>netsh interface ipv4 set subinterface "Ethernet" mtu=100
The parameter is incorrect.

Looks like Windows do not allow MTU size smaller than 352 bytes: https://support.microsoft.com/en-us/topic/packet-loss-occurs-when-mtu-is-below-576-and-pmtu-discovery-is-enabled-in-windows-e7a54c21-6202-9788-fb24-99530c0e9d64

Thank you.

Windows 10 Network
Windows 10 Network
Windows 10: A Microsoft operating system that runs on personal computers and tablets.Network: A group of devices that communicate either wirelessly or via a physical connection.
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  1. Leon Laude 85,666 Reputation points
    2021-09-01T10:09:39.447+00:00

    Hi @liujia ,

    The paremeter is incorrect because your MTU value of 100 is probably lower than the minimum MTU, to check your current minimum MTU run the following command:
    netsh interface ip show global. I believe the minimum MTU nowadays is 576 by default.

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    If the reply was helpful please don't forget to upvote and/or accept as answer, thank you!

    Best regards,
    Leon

    1 person found this answer helpful.
  2. Limitless Technology 39,366 Reputation points
    2021-09-01T13:52:39.11+00:00

    Hello @liujia ,

    Thank you for your question.

    Please follow these steps, it will help you:

    Open the command Prompt window and follow the steps below to change the MTU size:

    Type “netsh interface ipv4 show subinterface”.
    Press Enter.
    You will see a list of network interfaces.
    Type “netsh interface ipv4 set subinterface Local Area Connection mtu=1472 store=persistent”.
    You should replace Local Area Connection with the name that appeared in the “Interface” column from steps previous steps
    Press Enter.
    Type “netsh interface ipv4 show subinterface” to check the result.

    If the reply was helpful, please don't forget to upvote or accept as answer.

    1 person found this answer helpful.