Visitor III

Question

Disconnects with Windows 11 PC / 5G Router

Forum|Forum|2 years ago
March 11, 2024
14 replies
16620 views

Hi,
i'm using Forticlient VPN now since approx 1.5 years for work, without any problems.
Usually i connect over a DSL Line with a LAN-Cable connected to my Windows 10 PC.
Sometimes, due to provider problems, i also use a Mobile Data Card, which is operating in a 5G Router. It provides a Wifi net, which my W10 PC connects to and Forticlient also runs smoothly.

Recently, i got a second machine with Windows 11 installed. Over the "normal" house-Wifi everything also works but when i try to use the same 5G Router connection, which is still working on my Windows 10 machine, Forticlient connects and then always immediately disconnects. Tried also to connect the 5G Router with a cable, but same effect...

Maybe someone knows this kind of preoblems and may help. Would appreciate :)

Cheers

FortiClient

ezhupa

Staff

Hello @r4ndom81,

Have you run any ike debug on the FortiGate when trying to connect via FortiClient?
The commands would be as follows:
diagnose vpn ike log-filter dst-addr4 <Remote-GW> (your public IP address)
diagnose debug application ike -1
diagnose debug console timestamp enable
diagnose debug enable

May be useful:

Starting from FortiOS 7.4.1, the 'diagnose vpn ike log-filter dst-addr4' command has been changed to 'diagnose vpn ike log filter rem-addr4'.

Also I found this old post in the forum regarding issues with FCT and Windows11 but in this case it was not related only to a Mobile Data Card. Maybe it helps:
https://community.fortinet.com/t5/Support-Forum/Client-VPN-IPSEC-with-FortiClient-fail/m-p/281436#M223367

Best Regards,
Enea

r4ndom81Author

Visitor III

Hi, and thanks for the reply!

Could you elobarte some more - i sadly dont have any experience in running debug logs. Im just a (very) simple user which hasnt any clue about the deeper possibilities of the programm, forgive me.

Cheers

ezhupa

Staff

Hello,

Those commands would need to be run on the FortiGate where you are connecting if you are using an IPSEC VPN. In case of SSL VPN you would need to run other commands. Are you the FortiGate administrator and have access to the device??

AEK

SuperUser

Hi @r4ndom81

In case you are using SSL VPN, can you try disable IPv6 on your Windows 11 before connecting to VPN?

AEK

r4ndom81Author

Visitor III

Hi,
thanks. I think i ve disabled IPv6 (am not sure if this was right, cause im not into network settings, just a normal windows user), but forticlient didnt connect after that.

In general, the problems are still present with unaltered windows settings. Forticlient connects, i see a short upload and then disconnects...

Cheers

robR

Explorer

Hi Mate, Have you had any luck? Look like I have same issue. Worked fine for years, just stopped no reason. I have pulled everything apart and rebuilt with no luck, and my IT have walked away (du'h!).

I think it may be in the router, but that is so specific no-one can help.

Doesnt help that I am not an IT person, just an end user!

Sheikh

Staff

Hello @r4ndom81

What is the version of FortiClient ? Have you tried using a different version of Forticlient in Windows 11 ?

WiFi adapter drivers may need to be updated; this is just a suggestion; it is not guaranteed to work.

Moreover, Forticlient debugs and debugs on FortiGate would give some insights about the issue.

regards,

Sheikh

robR

Explorer

Hi Sheikh, I just raised a post similar to this. VPN just stopped working. My testing to date shows it blocks the connection to the machine at the router. My ISP wont help as they says its VPN vendor problem. All I want to know is if they have pushed a security profile update that has caused change, but no answer. I have totally rebuilt my machine from scratch twice and even gone from win11 to win 10 to test. I can access the vpn using an ios device through the router, just not a win machine. I have tired two differently configured win machines with same result. To you query I have installed a few different versions of the client to test, all same result, so have excluded the client. My pc firewall has passthrough configured so not that. I have checked all ip/dns etc and pinged network - all good until vpn connects then everything drops.

robR

Explorer

sorry, hit wrong button, too late at night.

AEK

SuperUser

Hi @r4ndom81

Do you confirm your VPN works from your Windows 11 when using DSL instead of 5G?

On the other hand I saw many similar issues with FCT VPN on Windows 11 due to NIC driver. So try change, upgrade or even downgrade your NIC driver.

AEK

r4ndom81Author

Visitor III

Yes, on the "house" wifi (its a cable/coaxial dsl connection from a german company called "vodafon") everything works fine.

Yeah, my company mentioned that downgrading might work but the "roll-back" button in the device manager is disabled so nothing available and when hitting "update driver" it says its on the latest.
I dont know on which version i should up-/downgrad or where i may get the drivers.
As said, reeinstalled the ethernet drivers this morning, grabbed from the minisforum page (intel (R) Ethernet Controller I226-V) but with no luck.

Sorry, im just a intermediate windows user.....

r4ndom81Author

Visitor III

...got the chance to roll back on this ethernet driver but same effect. Got message from my company, which also looks into the problem and it seems that indeed my windwos 11 ethernet isnt working with forticlient (bug). They suggested roll back to windows 10 but this isnt an option for me atm. First have no license adn second would be much work to redo the whole system.

So this is very unfortunate that forticlient doesnt work with some windows-versions/ethernetcards :(

Umirzak

Visitor III

i have similar issue with my users, they randomly disconnecting from VPN,

we are using IP Sec VPN, just raised official support ticket, waiting for the solution.

r4ndom81Author

Visitor III

So even the connection works with the Smartphone wifi hotspot (over my Pixel 8, as i statet before) it seems that wireing it over usb (teethering) also leads to the disconnects of forticlient.

robR

Explorer

Hi @r4ndom81

An update from my experience for what it is worth. Turns out it was my ISP (Telstra Australia). I had to raise a complaint to their complaints department after their support team refused to discuss my problem - because I was having an issue with a VPN (they assuming like NORD etc) it was out of their cope to provide support. I could not get them to engage in discussion. I did not blame them or ask for resolution, but simply politely asked 2 questions - 1. Has Telstra undertaken any security updates in the time the service was affected and 2. Does their proprietary router system allow for the passthrough. I had similar issue as you describe... once the VPN connected, LAN was disconnected, then VPN dropped. Oddly I could hotspot via an IOS device and it would work through the same internet connection.

Finally the Telstra complaints department undertook an investigation - not into my technical problem, but the way in which their support team had interacted with me (I had transcripts where they flat out refused to discuss my problem) it was discovered that indeed Telstra had pushed new policy settings into customer routers and there were a number of customers with affected services and the policy settings were being rolled back. Within 24 hours I noticed that that my router had been remotely factory reset (all of my static IP's had been erased) the VPN suddenly just worked as before. Anyhow - dont assume its your system or Fortinet.

r4ndom81Author

Visitor III

Hey folks,
so update from my side: Downgraded the Mini PC to Win10 Pro now but the problem PERSIST!

Its soo strange: The 5G Router still works perfectly with my othe Win 10 PC but not on the said one, so @robR I think its also not a provider thing.

Dont know what i can do anymore unfortunately....

AEK

SuperUser

I wonder if it has something to do with IPv6.

Can you try this?

In case your router gives you an IPv4 address, then try force it to give you an IPv6 address only
And in case your router gives you an IPv6 address then try force it to give you an IPv4 address
Also try by disabling IPv6 on your Windows network interface (or WiFi) connected to the router

AEK

r4ndom81Author

Visitor III

Hey,
thanks @AEK. So what i did and whats the results are the following:

- Disabled IPv6 on the Ethernet Adapters Properties (unchecked in the "Networking-list")
--> Forticlient connects somehow: Bytes are send, the "Fortinet Virtual Ethernet Adapter" gets enabled, no bytes are recieved AND my Internet connection is completly gone on the PC.

- For the sake of completeness - with default settings (IPv6 and IPv4 enabled on the Ethernet Adapter): Forticlient connects, "Fortinet Virtual Ethernet Adapter" enables, Forticlient Window freezes for a short time and disconnects (jumps back to login Window), also the "Fortinet Virtual Ethernet Adapter" disables).

Did you ment that procedure? If so, its no solution unfortunately - In addition i dont know whats going on on the Router side: As said, its a mobile 5G Router [ZTE MU5001] with very little settings, so i cant see whats been provided in terms of IP6 or IP4, on the device. Or do i need to check this somewhere else? Im a long term windows user but no network specialist, so i dont know exactly if i did right or where exactly i can grab necesary informations.

As so often mentioned, i run the exact same setup on my other Win10 PC (nothing modified on the networking properties at all) and everything works perfectly over the 5G router.

I attached a screensot of whats additionally in my Network connection window: (Virtual)Ethernet is the one which connects shortly when using Forticlient, (Virtual)Ethernet 2 isnt doing anything at all and stays like this.....and i did enbaled disabled the IPv6 thing on my normal Ethernet Controller though, not on these virtual ones.

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