Windows 7 L2TP over IpSec VPN


  • Hi all, 

    Having a real tough time getting Windows 7 machines connect to my Draytek Vigor 3900 VPN. 

    I know it's not an issue with blocked ports or firewall issues as all of the computers using W10 connect to the VPN no problem however W7 machines can never connect. 

    I connect by using the Draytek Smart VPN client which also does the registry changes. It hangs on dialing for about 60 seconds then just says 'Unknown Error' 

    If I try to use the inbuilt W7 VPN, I have no luck at all and get given error 809 

    I can use the exact same config and same user on a W7 machine and it just wont connect at all

    I have added/modified the 'AssumeUDPEncapsulationOnSendRule', 'ProhibitpSec' and 'AllowL2TPWeakCrypto' registries.

    I have made sure the 'IKE and AuthIP Keying Modules', 'IPsec Policy agent', 'Remote access auto connection manager', 'remote access connection manager', 'Routing and remote access' and 'Secure socket tunneling protocol service' services are all set to automatic start up and are running.

    The last 2 days every bit of help I've seen points to the AssumeUDPEncapsulation.... reg edit but that hasn't fixed my problem.

    Has anyone had this issue before? I am trying to connect on a Toshiba Tecra but I don't think the laptop is the issue as the W10 Tecra's connect with no problem. I do not have the Intel Proset wifi management software installed. 

    Thanks in advance.


    Tuesday, July 10, 2018 12:36 PM

All replies

  • Hi,

    Thanks for your question.

    Due to this windows registry key “AssumeUDPEncapsulationOnSendRule” related to L2TP over IPsec, we could first test changing to basic VPN tunnel protocol on the VPN server for windows7 client to see if it works.

    Because the registry key need to be configured both on server and client, we need to check the VPN server. However, the issue is related to third party products Draytek, we could also consult the vendor the compatibility between the device and windows7 and the configuration if it is correct.   

    Here’s a link discussed about L2TP-VPN Error809 connect to third party VPN server from Windows7, it may be helpful.

    Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.

    Reference link:

    Hope above information can help you.

    Highly appreciate your effort and time. If you have any question and concern, please feel free to let me know.

    Best regards,


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    Wednesday, July 11, 2018 3:16 AM
  • Hi,

    Just checking in to see if the information provided was helpful. Please let us know if you would like further assistance.

    Best Regards,


    Please remember to mark the replies as an answers if they help.
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    20 hours 23 minutes ago