Disconnects with Windows 11 PC / 5G Router

[r4ndom81]

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

[Sheikh]

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]

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.

[r4ndom81]

Hi,
got into this only now and retried everything this morning.
Unfortunately the problem persists. I updated Forticlient to the latest 7.2.4.0972, updated my 5g router and even reinstalled the ethernet drivers (version from the pc's manufature). Nothing seems to help:
Over LAN-cable (from the 5g router directly to my pc) or over the provided wifi, forticlient connects and instantly disconnects. Internet connection is totally fine still.

Im a little frustrated by now :( ....as said im a enduser with no access to some fortigate or such. Just got the forticlient link from my company to use it for my remotework.

If theres anything i can do or someone has an idea, i would much appreciate.

Cheers

[robR]

sorry, hit wrong button, too late at night.

[AEK]

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.

[r4ndom81]

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.....

[r4ndom81]

...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 :(

[r4ndom81]

Correction: They think not the ethernet controller is the problem since my hardweare doest seem to have the bug (intel - realtek might have that). They "suspecting the 5g mobile router might not like our IPSEC Forticlient VPN"

[AEK]

So if I understand well there is some kind of incompatibility somewhere between the threesome Wondows11-FortiClient-Your5G.

Can you try from a 5G connection of another operator or another 4G connection if available.

[r4ndom81]

Can try a wifi over my phone. WIll report