locked
VPN connection problems - L2TP on Windows 10 RRS feed

 > 

  • Question

  • Question
    Sign in to vote
    0
    Sign in to vote

    I have been working from home for many months and connecting to my office VPN via L2TP protocol successfully the entire time. Recently, it stopped working completely. I tried connecting from several different computers in my house and all had the same issue. I thought the problem had to do with the ISP so they came out to replace the modem. After the modem was replaced, I now have one computer (my wife's) that is capable of connecting to the VPN. However, all of the other computers I have tried have been unable to connect.

    I have gone through a lot of the typical troubleshooting advice for VPN error 789 including reinstalling the network adapter, checking to see if the IKE and IPSec services are running, confirming the pre-shared key is correct, opening ports 500 4500 and 1701 on firewall, etc. The only difference I can see between my wife's computer and the others is that her computer has McAfee security tools installed which are running instead of windows defender. The other computers are using windows defender / windows firewall. However, I tried disabling windows firewall entirely and it still didn't solve the problem.

    I am nearly at wits end on this issue. Please help.

    Friday, August 14, 2020 2:20 AM

All replies

  • Question
    Sign in to vote
    0
    Sign in to vote

    Hi,

    In regards to your issue, I want to confirm these information first:

    1. Is the error message "Remote Access error 789 - The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer"?
    2. Do you use a L2TP/IPSec protocol with pre-shared key?
    3. Is your L2TP/IPsec server behind a NAT-T device?

    After researching solutions to VPN error 789, here're my suggestions:

    1. In a similar case like you, he solved the problem by (1) Updating his router (2) Make sure that "IKE and AuthIP IPSec Keying module" and "IPSec policy agent" in service is set to Automatic mode. 

    Windows 7 IPSec/L2TP VPN connection problem



    2. If your L2TP/IPsec server behind a NAT device, you have to build the AssumeUDPEncapsulationContextOnSendRule registry key.

    To do this, locate and then click the both following registry subkeys:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IPSec

    On the Edit menu, point to New, and then click DWORD (32-bit) Value for both two paths.

    For more details, you can refer the following link:
    How to configure an L2TP/IPsec server behind a NAT-T device in Windows Vista and in Windows Server 2008

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


    • Edited by Gloria Gu Friday, August 14, 2020 6:41 AM
    Friday, August 14, 2020 6:40 AM
  • Question
    Sign in to vote
    0
    Sign in to vote
    Hi,
    Just want to confirm the current situations. Please feel free to let us know if you need further assistance.

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

    Monday, August 17, 2020 8:47 AM
  • Question
    Sign in to vote
    0
    Sign in to vote
    Hi,
    Just want to confirm the current situations. Please feel free to let us know if you need further assistance.

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

    Friday, August 21, 2020 7:15 AM