FortiClient drops traffic every few minutes, could not find interface for local_gwy

[moryasena]

We are seeing this issue with FortiClient 7.0.6 and 7.0.7, both the free and paid/licensed EMS version, on some of our endpoints. It seems like an endpoint becomes 'cursed' and after this point, no amount of clean uninstalling/reinstalling will fix it.

I have tried doing a full uninstall, FCRemove, running the WAN Miniport repair tool + reinstaller, and a clean FCT reinstall and the issue still happens. I was just connected on a test device and it started dropping at 20 minutes, then 15, then 10, then 5, then it was almost immediately.

We've seen this on various versions and editions of Windows at various states of patching/feature upgrade installation. Never had this problem until 7.0.x. We've updated chipset, motherboard, and NIC drivers on them as well, with no change.

Does anyone have any ideas? I have a case open with TAC but historically the troubleshooting of these issues has been so slow that we ended up wiping the device and starting over - interestingly, on one device the problem came back even after that! It seems to be mostly Realtek network adapters that have this issue.

[gfleming]

What are the symptoms here? Are you losing all network traffic or just VPN connectivity?

The "could not find interface for local_gwy" is that an error message that pops up? When and where do you see it?

[JohnP]

I’ve had a few run-ins with "could not find interface for local_gwy" and the problem in our case we had an old VPN network interface causing the problem. It was a CiscoAnyConnect adapter.  We found the solution by disabling all other interfaces on the PC, only using the Wireless interface and the FortiClient VPN add ones. Once stability was confirmed we removed the CiscoAnyConnect adapter permanently and enabled the others.