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Windows Server L2TP vpn not connecting from external network RRS feed

  • Question

  • Hi everyone,

    I'm looking for a little help with an issue that is driving me crazy. I am setting up a new Windows Server 2016 L2TP VPN server and I can not get a connection from an external network.

    Internally it works fine if I connect from a device attached to our internal network. It doesn't matter if the device is a domain PC on our wired network or an IOS device just connected to our internal wifi, they connect perfectly.

    Externally I can ping the address, I can see in the firewall log that UDP ports 500 and 4500 are passed through but never see UDP port 1701. I tried completely disabling the firewall and I get the same behavior. Windows devices seem to connect, authenticate, but fail on completing the connection. IOS just gives a generic error "the server did not respond".

    The server is a domain member with 2 nic's, 1 internal 1 external. L2TP/IPSEC with pre-shared key. Windows Firewall has UDP port 500,4500, 1701 and protocal 50 open.  

    Anyone have any thoughts?

    Thanks in advance!

    Thursday, February 1, 2018 8:34 PM

All replies

  • Hi,

    I didn't found any related information about ios access to internet via NPS in Microsoft official documents. Also, I will continue to research and text in the future.
    If we have any updates about this issue, we will keep you posted as soon as possible. Your kind understanding is appreciated.  

    Best Regards,

    Frank


    Please remember to mark the replies as an answers if they help.
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    Friday, February 2, 2018 6:10 AM
    Moderator
  • Hi Frank,

    Thanks for the reply.

    This isn't an ios specific problem.  Neither windows clients or ios clients can complete the connection to the vpn server from an external network.  They both connect fine from our internal network.

    Best regards,

    Craig

    Friday, February 2, 2018 12:58 PM
  • Hi,
    Based on the complexity and the specific situation, we need do more researches. If we have any updates or any thoughts about this issue, we will keep you posted as soon as possible. Your kind understanding is appreciated. If you have further information during this period, you could post it on the forum, which help us understand and analyze this issue comprehensively.
    Sorry for the inconvenience and thank you for your understanding and patience.
    Best Regards,

    Frank

    Please remember to mark the replies as an answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com


    Monday, February 19, 2018 1:51 AM
    Moderator
  • Was there any advance on this issue since February? I´m struggling with the same issue here. Router : RV082 Cisco Small Business. Thank you for your updates!
    Tuesday, September 18, 2018 9:19 PM
  • Was there any advance on this issue since February? I´m struggling with the same issue here. Router : RV082 Cisco Small Business. Thank you for your updates!

    You should open a new thread, as the router add some informations.

    For the OP the Windows Server was directly on the internet on one NIC, unlike you with a router as I see it.


    Regards, Philippe

    Don't forget to mark as answer or vote as helpful to help identify good information. ( linkedin endorsement never hurt too :o) )

    Answer an interesting question ? Create a wiki article about it!

    Wednesday, September 19, 2018 1:06 AM
    Moderator