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2017-01-16 Utorrent

Fix Utorrent making your Router disconnect from the Internet

This issue is caused by the MTU(Maximum Transmission Unit) as pointed out by alex1911 on a private internet access forum. It should be changed from the 1500 default value.

  1. Open CMD by clicking start icon Command Prompt(Admin) and paste this command:

    ping www.google.com -f -l 1500

    If you will see the message like: Packets need to be fragmented but DF set, drop the test packet size down (10 or 12 bytes) and test again, to 1490 - 1480 - … Drop the test packet size down more and test again until your reach a packet size that does not fragment.

    Once you have a test packet that is not fragmented increase your packet size in small increments (1-2 bytes) and retest until you find the largest possible packet that doesn´t fragment.

    Take the maximum packet size from the ping test and add 28. You add 28 bytes because 20 bytes are reserved for the IP header and 8 bytes must be allocated for the ICMP Echo Request header.

    In my case the latest stable one was 1454 + 28 = 1482 < This is my optimal and workable MTU packets.

  2. Apply settings to your ( VPN / LAN connection ). Open CMD as Admin and type:

    netsh interface ipv4 set subinterface "Your LAN NAME GOES HERE" mtu=PASTE HERE Optimal value store=persistent

    and press on Enter. Repeat with IPV6 the same command:

    netsh interface ipv4 set subinterface "YOUR LAN NAME GOES HERE" mtu=PASTE HERE Optimal value store=persistent

    Repeat all these operations with all network adapters that you have. If you are using PIA it should be called Ethernet2 and Ethernet re-check names in “Open network and sharing center” so these commands will sound something like this :

    netsh interface ipv4 set subinterface "Ethernet 2" mtu=1480 store=persistent
netsh interface ipv6 set subinterface "Ethernet 2" mtu=1480 store=persistent
netsh interface ipv4 set subinterface "Ethernet" mtu=1480 store=persistent
netsh interface ipv6 set subinterface "Ethernet" mtu=1480 store=persistent

  3. After these will be done, re-check if they set correctly by opening command prompt(CMD)as admin again and post this:

    netsh interface ipv4 show subinterfaces netsh interface ipv6 show subinterfaces

Source#