DLAN and VPN connection Drops

Hello all,

I work in IT and have a customer who has problems with the VPN.

He has a notebook Lenovo L580 with Windows 10 and uses L2TP over IPsec. He bought Devolo DLAN so he has LAN over the wall socket.

He complains that his VPN connection drops at irregular intervals.

My question, can DLAN basically cause VPN connection problems like this?

He doesn’t believe me. He has no other internet problems and the power lines are new. He said that.

I have 400 users also using the same laptop and VPN and so far I have had no complaints.

Best regards

First question is who is dropping the link? Is it from the VPN side or the client PC side. If it’s the VPN side then there may be VPN logs to check. Maybe the client also keeps logs (or can be requested to do so.)

Yes.

Powerline adapters are notorious for causing problems with VPN. I have 1000’s of VPN users and the first question asked if they are having VPN problems is are you using a WiFi extender or a powerline adapter.

If the answer is ‘yes’ then 95% of the time using a cable into the router solves their VPN problems.

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The disconnections are client-side.
If you use the Windows integrated VPN solution (L2TP over IPsec) where do you find the log files in the event log?

What are the technical reasons why VPN connections have problems with DLAN or Power LAN? My argument has always been that if there are several intermediate stations between the router and the client, this is not optimal for a VPN tunnel. A VPN tunnel needs a direct connection if possible. So that it runs reliably.

As described above, my customer refuses and does not believe me. A really hard case.

Would it be possible to have them try 24 hours of a replacement (a very long Ethernet cable maybe)? If they replace the Ethernet over powerline and the problem immediately goes away then that would be the proof you would need, no?

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I have already made this suggestion to the customer. The customer is very difficult and does not want that. He does not want to change his infrastructure. That is what he said.

I have looked at his VPN logs and the following message always appears when his VPN connection is interrupted.

Error 829 (ERROR_LINK_FAILURE)

Message: The modem (or other connecting device) was disconnected due to link failure.

This error appears when the modem (in the case of dial-up or broadband connections) or tunnel (in the case of VPN connections) is disconnected due to a network failure or a failure in the physical link to the modem. The following are possible reasons for the failure.

  1. A problem in the network between the modem and the RAS server might have caused the basic dial-up or, in the case of a broadband connection, PPPoE connection, or VPN tunnel to fail.
  2. Check connectivity between the modem and the telephone/cable connection jack. If an external modem is being used, check the physical connectivity between the modem and the computer.
  3. In the case of VPN connections set up over a wireless network, problems in the wireless network might have caused the connection to fail. Check the status of the wireless connection in Network Connections folder. Some of the causes of problems in the wireless network are:
  • The wireless access point might have gone down due to loss of power or for other reasons.
  • The user’s computer might be out of the operating range of the wireless network or the RF signal strength might be weak.

I think you need to prove that his set up is the cause of the disconnections.

Normally you would take some troubleshooting steps by starting connected directly to the router and then if that works ok then you move back through any switches, access point or whatever he has, but it sounds like he doesn’t want to do that.

Don’t know whether your VPN policy allows you to connect to local resources when the VPN is connected, but a simple ping -t to the IP of his local router and another one to an internet IP (8.8.8.8) for example, you would expect to see these timing out around about when the VPN drops.

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“I’m sorry sir, but you’re the ONLY customer reporting these problems, so we presume it is an issue with your site. Additionally, you are the ONLY customer using powerline Ethernet, and as near as we can tell it is probably that configuration which is the source of your problems. If you are unwilling to test an alternate configuration to eliminate that possibility, then we must pause/close the ticket until such time as you are willing to work with us toward a resolution.”

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I’ve been using DLAN for over a decade, Devolo for around 4 years. They have been 100% reliable.

I spend around 8 - 10 hours a day connected to L2TP VPNs with no dropouts.

It probably isn’t the Devolos per se. It could be something on the line that is causing problems. I did have a 6 plug extension with a transformer for charging up to 4 USB devices. It was very “dirty” and caused enough interference that the throughput of my DLAN dropped to around 5mbps. Removing the dirty extension lead from the set-up restored it to full speed.

Does he have a fridge, for example, on the same circuit? They can be very “dirty”, when they turn the compressor on and off, causing huge spikes. Likewise microwaves can cause a lot of problems. The route between the two devices needs to be as free from noise makers as possible.

We also have a couple of users who have dodgy DSL connections, the VPN drops repeatedly, because they can’t get a decent connection between the house and the cabinet, especially when the neighbours are at home as well.

Another thing to try, which has often had success for our users who suddenly have problems, is to go into the Networt Setting (new Windows 10 settings) → Status and scroll down. Towards the bottom is an option to reset the network connection. This usually works on setups that refuse to connect at all, rather than random drop outs, but is probably worth doing, just to remove the PC itself from the equation.

(my setup is DSL router in the hall → DLAN in hall → DLAN in office → Firewall → switch → PC / WLAN access point → wireless bridge to other access points. This works 100% reliably, but the DLAN can have problems with dirty devices on the line, as described above.)

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My boss is very good, when it comes to this. If it isn’t the laptop and it isn’t our end, it is the users network and if they aren’t willing to follow our advice or carry out tests under our guidance, they have to sort the problem out for themselves. As we test all of the laptops, before they are sent to the users, we know the devices are working and we know whether the infrastructure is working (the IT is 75% in home office and working over VPN), we usually know that it is the users network - we will try re-creating the VPN connection properties and doing a network reset, if that doesn’t work, they have to follow our guidance advice or sort it out themselves; although 2/3 of the problems have been down to the ISP.)

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This. 100% this @RainbowNerd

Thank you all for your effort and responses.

The clarification with the user is my business. Technically, I now know that there are problems in connection with Power LAN or WLAN Repeater when using VPN connection.