I have a laptop (Dell XPS-15 9560) running FortiClient 6.x SSL VPN which connects through to a Fortigate firewall.
Over the past 18 months, the FortiClient VPN has been incredibly stable and unexpected VPN disconnections were rare. By rare, maybe once a week.
A few months back, the laptop had a Windows 10 feature update from 1909 to 2004 and from that day onwards, the VPN has started to behave unreliably. Disconnections are totally random, I can last 8 hours uninterrupted one day and the next day 10 disconnections throughout the day, some within 5 mintues of each other. I usually experience around 6 disconnections per day. Each time, the WiFi is still connected and I can immediately reconnect the SSL VPN with no issue.
I understand that a VPN relies on a solid uninterrupted network connection and if that fails, even briefly, it can cause the VPN to drop. What I cannot work out is why the VPN is dropping and why it started after my upgrade to Windows 10 2004.
I have investigated the usual stuff:
- My WiFi connection is stable, with strong signal and it does not ever drop out.
- My router is a high end ASUS model with the latest firmware
- I have tried 2.4 and 5 GHz WiFi connections with no improvement
- I have uninstalled/reinstalled the FortiClient software
- I have upgraded to the latest version of FortiClient
- I have uninstalled/reinstalled my WiFi adapter (Killer Wireless-n/a/ac 1535 Wireless Network Adapter)
- I have checked on Dell's website for newer network drivers
- I have run diagnostics on the FortiClient. It identifies a disconnection, but offers no real information that points me to the issue
- I have checked Windows Event Logs for any relevant issues at the time of VPN disconnection
I have another laptop, also connected through WiFi to the same ASUS router. This is running the same FortiClient, and this has a solid, reliable SSL VPN connection with no random disconnects. This is also a Dell laptop running Windows 10 2004, but with a different brand of network adapter.
I am convinced the issue is related to the Windows 10 feature upgrade to 2004, because the issue started within hours of the upgrade, but I cannot think of any resolution.
Any help or troubleshooting suggestions would be really appreciated. Thank you!
Best Answer
I think I finally got a fix to this issue. The problem was not with Windows 10 feture update 2004, but the WiFi card vendor's 'enhanced' WiFi management software which was running in the background. The management software is appropriately named 'Killer Control Center' (Killer being the name of the WiFi vendor) and it was performing 'intelligent' optimization of my networking. I have no idea what it was doing that caused my VPN connection to randomly drop, but as soon as I disabled it, my VPN connection became stable again.
The upgrade to Windows 10 feature update 2004 must have triggered Dell Update to update my network software/drivers which must have installed Killer Control Center.