Slow Speed and DNS Leak via VPN

Discussion in 'Installation and Configuration' started by EricY6, Feb 3, 2023.

  1. EricY6

    EricY6 Bit Poster

    For those using VPN with your Parallels Windows 11 VM, do you experience slow speed? I'm pretty sure there is something in the Parallels network layer that slows down the connection.

    1. If I'm connected to VPN on Mac OS, my VPN speeds on Mac OS are around 250mb down/80mb up (after multiple testings). But in Parallels, where it's supposed to transpose from Mac's network connection under Shared Network mode, I'm only getting around 150mb down/1mb up. Yes! that's ONE MB up, if I'm lucky.
    2. I tried to switch to Bridge network mode for Default Adapter, then initiate the VPN connection within Parallels. Same results.

    Without VPN connection, Parallel's Win 11 VM network speed seems to be on par with my network line. So it looks like there is something in Parallel's network layer that causes the slowness.

    Another proof is Parallels' network layer has DNS-leak. On the Mac OS, after VPN is connected, visiting AWS services recognized my IP address location from the VPN connection. But in Parallels, AWS knows my true location.
  2. Pavel Merkulov

    Pavel Merkulov Parallels Support


    Thank you for your feedback.

    To eliminate the probability of any browser or network adapter misconfiguration, please perform the following steps:

    0. Take a snapshot of the virtual machine: Run the virtual machine and in the top menu click Actions > Take Snapshot.

    1. Install and run a stand-alone application:

    2. If results are similar to that in browser, please take a screenshot of its results and proceed to the next step.

    3. Shut down your virtual machine (Actions > Shut down). If it is in a suspended state, resume it and then shut down.

    4. Open the virtual machine's Configuration: click Parallels icon || > Control Center > right-click on the virtual machine > Configure.

    5. Go to Hardware > Network and then in the bottom left click "-" to delete the network adapter from the virtual machine.

    6. Then click "+" > "Network" to re-add the network adapter.

    7. Run the virtual machine and see if the issue persists.

    If the issue does persist, perform the following steps:

    (these steps will reset the network settings on the macOS side)

    1. Shutdown virtual machine down (Actions > Shut down).
    2. Quit Parallels Desktop (Parallels Desktop icon || > Quit Parallels Desktop).
    3. Open Terminal (Finder > Applications > Utilities > Terminal) and execute the command below:

    sudo rm /Library/Preferences/SystemConfiguration/preferences.plist

    4. Hit Enter. Once prompted, enter the password from your Mac and press Enter.
    5. Then execute the command below:

    sudo rm /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist

    Hit Enter

    6. Restart your Mac.
    7. Then start the virtual machine and check if it works.

    If the issue does persist, collect an additional technical report (click Parallels icon || > Help > Send technical data > check "Attach screenshots..." > press Send Report) and send the report's 9-digit ID .

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