Windows 10: L2PT VPN connection restricts internet connection

I am currently working from home and connecting to my work PC via L2PT VPN connection and Remote Desktop Connection. It is working perfectly fine on Windows 10. However, If I do a fresh install on Windows 11, the connection is fine for a couple of hours and then for some reason I can not get more then 1/2 mbpr when connected to the VPN, while before that I am getting around 100 mbpr. I have done all the guides that are available on the Internet, but nothing is helping.My laptop is Lenovo Leagion 5 pro.

:)

 

L2PT/IPSec VPN connection fails when using Wi-Fi

Connecting to an L2PT/IPSec VPN connection fails when using a Windows 10 computer connected to the network by Wi-Fi. The error obtained is the following:





I am sure the VPN settings are correct because I can connect to the VPN with the same computer, when the computer is connected to the network by Ethernet. Moreover, I am positive there is not a firewall in the way either, because I tested with another computer
using Ubuntu Linux, and I was able to connect to the VPN over Wi-Fi and Ethernet. Here is a list of the tests I ran:

• Connection to VPN is sucessfull on Windows 10 when using Ethernet and Windows Firewall on.
• Connection to VPN fails on Windows 10 when using Wi-Fi and Windows Firewall on or off.
• Connection to VPN fails on Windows 10 when using both Wi-Fi and Ethernet network connections.
• Connection to VPN is sucessfull on Ubuntu Linux when using Ethernet or Wi-Fi and UFW firewall on or off.

All test were run with the computers connected to a TP-Link SR20 router as the DHCP server and gateway. The router has the L2PT and IPSec pasthrough settings enabled. The antivirus used in the Windows 10 computer is Avira (free edition).

What is preventing the VPN connection when using a Wi-Fi network connection on Windows 10?

Thanks

 

No Internet Connection When VPN Is Connected

This particular issue has been going on for almost a month now. My companies IT department is still trying to figure out the root cause. Below is a list of isolation / troubleshooting i've done.

Issue: Once connected to the work VPN (successfully) the internet connection on the Windows 10 machine disconnects and does not allow any network traffic.

OS: Windows 10 Home - Version: 1909 (OS Build 18363.476)

Computer: Razor Blade 2019

- Latest drivers installed

- Latest Windows updates installed

- System Wide issue

Troubleshooting / Isolation

• Cellular Data: Verified the Windows machine can connect to a hotspot and successfully browse the internet. (No VPN involved)

• Cellular Data + Work VPN: Verified the Windows machine can connect to the hotspot & successfully connect to work VPN and successfully browse the internet.

• Home WiFi: Verified Windows machine can connect to the home wifi network and successfully browse the internet (No VPN involved)

• Home WiFi + Work VPN: Verified Windows machine can connect to home WiFi. It can successfully connect to work VPN. However once the work VPN is connected, the home WiFi network indicates (No Internet Access)

• Ping Test + Work VPN: Verified I can successfully ping (work) websites and even the work VPN URL successfully without any packet loss. However once I go to ping (non-work) related addresses like google.com, apple.com etc. there is packet loss.
  

At this point I decided to test my work VPN on my iPhone & Apple Mac.

• iPhone: Home WiFi + Work VPN: Verified the iPhone successfully connects to home WiFi network and the work VPN and can successfully browse the internet.

• Mac: Home WiFi + Work VPN: Verified the Mac successfully connects to home WiFi network and the work VPN and can successfully browse the internet.

Isolated: Only the Windows machine seems to be affected. I even verified this issue occurs on multiple Windows user accounts on the Windows 10 machine.

- Windows 10 is fully updated to the latest November Windows 10 update and issue persists

- Deleted and Added the VPN configuration several times and issue persisted.

Third Party VPN Client Test: Tested with Nord VPN and the Windows machine successfully connected to the home WiFi network & the Nord VPN connection successfully connected to a random server and successfully browsed the internet.

- Disabled IPV6 on VPN & WiFi network configuration (Per IT Support guidance) and issue persisted

*Currently updating to Windows 10 Insider Preview 19033.1 (vb_release) to see if this might fix anything pertaining to Windows 10 VPN.

Thanks for any additional guidance / suggestions / help that the community offers.

 

L2PT/IPSec VPN connection fails when using Wi-Fi

Marvelos Reg,

I will contact my ISP (Spectrum Charter) about it, but can you explain why is this necessary?

The VPN connection works when the computer is connected to my local network using an Ethernet cable as the access point. However, it does not work when I use a Wi-Fi access point to connect to the same network (regardless of the band, I tried over 2.4 and
5GHz). Moreover, other computers using a different OS (Ubuntu) can connect to the VPN from the same network (my local network) using both Ethernet and Wi-Fi access points. If there was something in the network (local network or my ISP's network) blocking L2PT/IPSec
connections or a NAT interfering with the packet routing, I would not be able to connect to the VPN from my local network using an Ethernet access point or another computer. However, I am able to do that, which shows my ISP does not interfere with VPN traffic.

That is my understanding, but I am not a networking engineer, so correct me if I am wrong.