FortiClient VPN-only (Windows) : Timeout While connecting to Public IP <****>

[Awash]

Hello,

FortiClient VPN version 7.4.2.1737 is still working on another PC, but the connection fails on a new PC using version 7.4.3.1790. The issue started after upgrading the FortiGate firmware from version 7.0.14 build 0601 to 7.0.17 build 0682. How can I resolve this issue? If anyone has encountered a similar problem, please share your solution.

[Yurisk]

Hi, version-sense there is no incompatibility - 7.4.3 FC should work with FortiOS 7.0.17. Have you looked at the known issues for the FC 7.4.3 if you are hitting some bug?

Like:

Bug IDDescription

1104520

When trying to connect to VPN, the connection status stuck at 98%.

https://docs.fortinet.com/document/forticlient/7.4.3/windows-release-notes/573433/new-known-issues

And if you happen to have FortiCare contract for Fortigate, you can still download previous versions of FC from support.fortinet.com, including 7.4.2

To debug, I'd start with the sniffer on Fortigate to see if FC is actually reaching it - dia sni pa any <IP address of the PC with FC as coming to FGT>

[Awash]

Hi Yurisk,

Thanks, I’ve already tried that, but it didn’t resolve the issue. As mentioned earlier, the problem is specifically with new PCs. The PCs that were previously connected using FortiClient VPN-only (IPsec VPN) continue to work without any issues. However, when I install FortiClient on a new PC, it times out during the connection attempt and fails to establish the VPN. I’ve already assigned an IP range for FortiClient, but since the new PC isn’t able to connect, the reserved IP doesn’t show up .. and as a result, the sniffer command doesn’t capture any activity.

When I run the sniffer command while connected from a working PC, it captures traffic as shown in the screenshot below.

[Awash]

I found a solution by downloading and installing an older version—it's working now.

https://support.fortinet.com/support/#/downloads/firmware

Thanks,

[GJStefou]

Just for future reference for others, 

I have seen the same behavior with FortiOS v7.2 too.

It solved the problem when i used FC VPN v7.2.

Hope this is helpfull for anyone.