L2TP: Windows 10 cannot browse Internet, Mac can

Rehy 1 Reputation point
2021-02-22T17:50:28.55+00:00

We have the strangest issue.

When we connect a Windows 10 Pro machine to L2TP, we can ping google.com (and any other external site) but cannot browse it both via IP nor URL - after a minute comes Time Out. We can access local resources.

Same network, same L2TP, but on a Mac - no issue.

We have tested 4 Windows 10 Pro machines on different builds, different networks / offices. Same issue. Reset one machine entirely to defaults - set up as personal computer. Same issue. No antivirus installed, Windows firewall disabled.

The registry tweak "AssumeUDPEncapsulationContextOnSendRule" doesn't have any effect.

It seems like it's in the OS settings? What else could have effect on this in Windows 10? How is Windows 10 handling L2TP differently from a Mac?

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. Sunny Qi 10,896 Reputation points Microsoft Vendor
    2021-02-23T07:38:52.75+00:00

    Hi,

    Thanks for posting in Q&A platform.

    When connect L2TP VPN successfully, may I know whether any other application which needs Internet access can work normally?

    Besides google.com, can you access to other URL such as youtube.com? Have you try to browse it via other browser?

    And here is an article regarding of configure L2TP VPN on Windows server 2019 for your reference.

    Set up L2TP/IPSec VPN on Windows Server 2019

    Best Regards,
    Sunny

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  2. Sunny Qi 10,896 Reputation points Microsoft Vendor
    2021-02-24T07:46:14.67+00:00

    Hi,

    Thank you very much for your feedback.

    My understanding is that you can connect L2TP VPN successfully but cannot access to the external sites. Please correct me if my understanding is wrong.

    This issue may occur if you configure the VPN connection to use the default gateway on the remote network. This setting overrides the default gateway settings that you specify in your Transmission Control Protocol/Internet Protocol (TCP/IP) settings.

    To resolve this issue, please configure the client computers to use the default gateway setting on the local network for Internet traffic and a static route on the remote network for VPN-based traffic.

    For more detailed steps, please refer to the following official article:

    You can't connect to the Internet after you connect to a VPN server

    Best Regards,
    Sunny

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