Sometimes it is necessary to reduce the MTU size of network interfaces. This post shows how to do it on Windows 10. Should work on not too old versions too.

Instruction

  1. Open the Window command prompt with the Administrator’s privileges using right klick.

    Right klick on Windows' command prompt to execute with Administrator's privileges

  2. Check current network interface settings and numbering with

    netsh interface ipv4 show interfaces

  3. Remember the interface number (column “Idx”) of the interface you like to change the MTU. In this example it is interface no. 6.

  4. Set the new MTU size - here we’ll set it to 1398

    netsh interface ipv4 set subinterface "6" mtu=1398 store=persistent

    Alternately you can use the interface’s name (here “Ethernet0”).

  5. Check, if your settings were accepted, again with

    netsh interface ipv4 show interfaces
    Right klick on Windows' command prompt to execute with Administrator's privileges

Common MTU sizes

MTU-size
1500 default on Ethernet networks
1492 common on PPPoE links
1398 safe setting, if you use a VPN over a PPPoE connection