Slow TCP Performance with OpenVPN/iperf3

Discussion in 'Windows 10' started by nechrist, Apr 22, 2018.

  1. nechrist

    nechrist MDL Guide Pack

    Apr 24, 2010
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    #1 nechrist, Apr 22, 2018
    Last edited: Apr 22, 2018
    Hi guys.

    As the title says, i'm doing some tests with openvpn and a vps with 1gigabit port (both directions). My ISP connection has around 160Mbit in down and 20Mbit in up.
    If i launch a speedtest while the VPN is active (under Windows 10 1803 17133.1) i have very poor performance: at the beginning of my tests i was reaching a super slow speed: about 20mbit in down. After some research and tweaking with openvpn configurations i managed to reach about 40 mbit in down which is still not enough. There is absolutely something wrong so i continued with experiments: i decided to give a try to the connection between me and the vps without going through the vpn. In this scenario the result with iperf3 is super clear: the connection between me and the vps is capped at around 50mbit. After some other tests and research, i got a doubt and i decided to try everything under a linux distro. So i ran an ubuntu live session on the same pc client i was using before and, big surprise, everything work as expected: i can reach max speed (around 160Mbit) in both iperf3 and openvpn. So, finally, i realized that the problem is something under Windows 10 indeed. I already tried with different settings of Autotuning level under the tcp/ip settings with no luck: the max speed i can reach is always 50mbit. The strange thing is that if i try to download something else from the vps (with chrome for example with http) i can get full speed instead: the only problems seems to be with openvpn and iperf and seem to be connected. Any clue about this?

    p.s.

    I forgot to mention that the vps runs Ubuntu Linux version 16 LTS
     
  2. Tito

    Tito Super Mod / Adviser
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    Nov 30, 2009
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    @nechrist

    1. Opt for 17134.
    2. Which interface is being used - ethernet or wlan?
     
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  3. pf100

    pf100 MDL Expert

    Oct 22, 2010
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    17133.1 is not 1803.
     
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  4. nechrist

    nechrist MDL Guide Pack

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    #4 nechrist, Apr 23, 2018
    Last edited: Apr 23, 2018
    (OP)
    Ethernet of course. Yes, this time i will wait for the 100% official one before install. They change something about tcp ip stack from 17133 to 17134?
     
  5. Tito

    Tito Super Mod / Adviser
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    What's the model of the ethernet card? And which driver version is installed?
     
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  6. nechrist

    nechrist MDL Guide Pack

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  7. nechrist

    nechrist MDL Guide Pack

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    Just for knowledge: i just installed 17134.1 and nothing changed, still the same results.