Unclean disconnect with IPsec VPN

[tola]

Hi,

I have multiple VPN connection installed in my machine. Some are windows native VPN connections and some Forticlient VPN connections. Forticlient version is 7.4.3.1790. Operating system is Window 11 with latest updates.

When i connect Forticlient IPsec VPN disconnect it and try to connect Windows native L2TP/IPsec VPN, it does not work, but returns error:
The L2TP connection attempt failed because the security layer encountered a processing error during the initial negotiations with the remote computer.

I found out, that windows VPN starts working again, if I stop "IKE and AuthIP IPsec Keying Modules" forcibly with command:
$ net stop "IKEEXT"

So is there some kind of "unclean disconnect" bug in Forticlient? Or could this be fixed with proper settings etc?

[Jean-Philippe_P]

Hello tola, 

Thank you for using the Community Forum. I will seek to get you an answer or help. We will reply to this thread with an update as soon as possible. 

Thanks, 

[Jean-Philippe_P]

Hello,

We are still looking for an answer to your question.

We will come back to you ASAP.

Thanks,

[Jean-Philippe_P]

Hello tola,

I found this solution. Can you tell us if it helps, please?

The issue you're experiencing with the L2TP/IPsec VPN connection on Windows 11 after using FortiClient could be related to the IPsec services not resetting properly. Here are steps you can take to address this:

1. Check IPsec Services:

   • Open Administrative Tools through the Control Panel.
   • Double-click on Services.
   • Look for "IPSEC Services" (including IKE and AuthIP IPsec Keying Modules, IPsec Policy Agent).
   • Ensure that the Startup Type is set to Automatic and the Status is set to Started. If not, double-click to change these settings.
     
     

2. Restart IPsec Services: After disconnecting from FortiClient, manually restart the IPsec services using the following commands in Command Prompt (run as Administrator):
   
   

   net stop "ikeext"
   net start "ikeext"
   

3. Check for Updates: Ensure that both FortiClient and Windows are updated to their latest versions, as updates may contain fixes for such issues.
   
   

4. Configuration Review: Review the VPN configuration settings in both FortiClient and Windows to ensure there are no conflicts.
   
   

If the issue persists, it may be beneficial to contact Fortinet support for further assistance, as there could be a specific bug or configuration issue that needs to be addressed.