If you can’t connect to your L2TP/IPsec VPN server from Windows 10, continue reading below to troubleshoot.
VPN connection errors can occur for a variety of reasons, but are usually related to incorrect VPN connection settings. (eg incorrect server name/address, authentication method, username or password). So, the first step in troubleshooting VPN connection problems is to check that all VPN settings are correct.
This guide provides instructions on how to resolve the following errors when trying to connect to an L2TP/IPsec VPN server on Windows 10 or Windows Server 2012/2016:
- A network connection could not be established between your computer and the VPN server because the remote server is not responding. This may be because one of the network devices between your computer and the remote server (such as firewalls, NAT, routers, etc.) is not configured to allow VPN connections. Contact your administrator or service provider to determine which device may be causing the problem.
How to fix: Unable to connect to VPN. Failed to establish an L2TP connection between your computer and the VPN server on Windows 10.
Before proceeding to the instructions below, do the following: *
* Important: If the problem started in January 2022first see the following article:
1. Ensure that the required L2TP/IPsec ports are enabled on the VPN server side.
Log into the Router on the VPN server side and send the following UDP Ports to the IP address of the VPN server: 1701, 50, 500 and 4500
2. Connect to the VPN through another device or network.
Try connecting to the L2TP VPN from another device (for example, your mobile phone) or network (for example, your mobile phone network).
3. Disconnect and re-establish the VPN connection.
Sometimes VPN connection issues are resolved after removing and re-adding the VPN connection.
If you still can’t connect to your l2tp/IPsec VPN server from your Windows 10 PC after the above steps, apply the following changes to your registry and VPN connection.
STEP 1. ALLOW L2TP CONNECTIONS BEHIND NAT.
By default, Windows does not support L2TP/IPsec connections if the computer or VPN server is behind a NAT. To work around this problem, modify the registry as follows:
1. Opening Registry editor. For this:
1. Press at the same time Win + R buttons to open the run command window.
2. Stand up regedit and press Enter To open the registry editor.
2. Go to this button in the left panel:
3. Right-click on an empty space in the right pane and select new –> A DWORD (32-bit) value.
4. For a new keyname type: UDEncapsulationContextOnSendRule and press Enter.
*Note: The value should be entered as shown above and no trailing spaces should be left.
5. Double click UDEncapsulationContextOnSendRule value, type 2 Scroll to Value Information and click OK.
6. Shut down Registry editor and restart car.
Step 2. Change the security settings on the VPN connection.
1. Rright click at Network Click and select the icon on the taskbar Open Network and Internet settings.
*Note: Alternatively, go Start > Settings press Network and Internet.
2. Choose Ethernet on the left and then click Change the adapter settings on the right.
3. Right click In VPN connection and select Characteristics.
4a. Yes Options tab, click PPP settings.
4b. Check Enable LCP extensions and press OK.
4c. Yes Security tab, check the following and click OK.
- Allow these protocols
- Challenge Handshake Authentication Protocol (CHAP)
- Microsoft CHAP version 2 (MS-SHAP v2)
5. Try connecting to a VPN. The connection should now be established without any problems. *
ADDITIONAL HELP: If you’re still having trouble after doing the steps above, try the following:
1. Check if the following services are enabled (Startup Type: Automatic)
- IKE and AuthIP IPsec key modules
- IPsec Policy Agent
2. If you are using a third-party firewall software, try disabling it or disabling it completely before connecting to the VPN.
3. To try reinstall the Windows firewall reset the settings to default. To do this, go to the address below Control Panel > Windows Defender Firewall and press Restore default settings.
4. Delete and to recreate VPN connection.
5. Restart VPN server side router.
That’s it! Let me know if this guide helped you by leaving a comment about your experience. Please like and share this guide to help others.