OpenVPN Support Forum

Ref: openvpn-install-2.4.8-I602-Win10.exe
Computers - 2 - One AMD based, the other Intel based. Both use the same LAN chip - Realtek RTL-8111
Realtek LAN driver 10.38.1118.2019 (latest available from Realtek)
OS - Win 10 Pro 10.0.18363.720

I am running an OpenVPN server in bridged mode on Windows 10 Pro.

I sporadically get a Blue Screen of Death (BSoD) and an automatic Windows restart as shown by the event log screen shot http://mpfrench.com/Critical_Errors.jpg. This server event happens whether or not the OpenVPN server is connected to a remote client.

I happened to be sitting at the computer console on two such events, 12 & 14 February 2020 and observed the BSoD on-screeen message: "SYSTEM_THREAD_EXCEPTION_NOT_HANDLED
BRIDGE.SYS"

It appears that there is a problem with the interaction of Windows BRIDGE.SYS, the Realtek LAN driver, and the OpenVPN TAP driver. However, even updating the LAN driver to the latest version does not solve the problem and I do not know of anything else that is under my control left to do.

I have the memory dumps from the last three BSoDs: http://mpfrench.com/MEMORY_20200212.DMP, http://mpfrench.com/MEMORY_20200214.DMP, and http://mpfrench.com/MEMORY_20200314.DMP

Frankly, it looks to me that there is a design problem with the OpenVPN TAP driver. Any other possibilities?

mpfrench wrote: ↑

Sun Mar 15, 2020 5:55 pm

it looks to me that there is a design problem with the OpenVPN TAP driver

That is entirely possible.

Note: The TAP driver source is currently receiving the TLC which it has needed for quite some time.

mpfrench wrote: ↑

Sun Mar 15, 2020 5:55 pm

Any other possibilities?

There is a preview version of openvpn which can be downloaded from the main DL URL which includes a WINTUN Driver, which will, most likely, cure the issue.

If all else fails then raising a bug report on trac would be the next best step.

I installed openvpn-install-2.5_git_wintun-I607-Win10.exe but could not get the WinTUN driver to bridge properly. The bridged connection would not allow connection to the Internet. However, I was successful in getting the TAP driver to bridge to the LAN adapter and will run this way to see if the system stability is affected.

Yeah, now that I think about it, WINTUN probably does not support TAP mode.

However, due to recent developments the TAP Adapter is getting a lot of developer time.
If you want to follow more closely, I suggest you subscribe to the developer mailing list.

After I installed openvpn-install-2.5_git_wintun-I607-Win10.exe on 15 March 2020, I encountered the first BSoD early this morningm 19 March 2020. I've added the memory dump to my site for download at http://mpfrench.com/MEMORY_20200319.DMP in case it helps the developers find the root cause of this problem.

I installed openvpn-install-2.4.9-I601-Win10.exe on 20 April 2020 and received another BSoD on 24 April 2020. The Windows 10 memory dump (~1 GB) may be downloaded from http://mpfrench.com/MEMORY_BSoD_20200424.dmp if any developer wants further detail. It still appears to me that there is an unhandled exception in the Windows TAP driver that is the root cause of this problem.

You are still the only person with this complaint .. maybe the fault is your end ?

I wonder how many people are running OpenVPN servers on Windows 10 in a bridging configuration. This is the only way that I've encountered this problem. The problem is due an adverse interaction between Windows and the TAP when in a bridge between the network adapter and the TAP adapter.

This problem is esoteric enough that it would take a TAP developer to trouble shoot. I don't know how to do so. I included the memory dump so that someone more knowledgeable than I am could perhaps find the exact unhandled exception and formulate a fix.

FTR:

mpfrench wrote: ↑

Sun Mar 15, 2020 5:55 pm

BSoD on-screeen message: "SYSTEM_THREAD_EXCEPTION_NOT_HANDLED
BRIDGE.SYS"

not tap09xx.sys

And, I doubt any volunteer developer for OpenVPN is willing to trawl through gigabytes of data to find an issue for M$ for free.

Sadly, I believe you are stuck with your issue.

Try a new PC or something ...