Opened 7 months ago

Last modified 6 months ago

#1385 new Bug / Defect

Bridged Windows 10 Causes Sporadic Crashes

Reported by: mpfrench Owned by:
Priority: major Milestone: release 2.5.3
Component: Generic / unclassified Version: OpenVPN 2.5.0 (Community Ed)
Severity: Not set (select this one, unless your'e a OpenVPN developer) Keywords:
Cc:

Description

This bug is a continuation of bug 828 which I mistakenly thought was repaired in OpenVPN version 2.5.0. However, the frequency of the computer crashes has diminished in version 2.5.0 compared with earlier versions.

I maintain three Windows 10 servers that each run OpenVPN 2.5.0. All have exhibited this same flaw - sporadic crashes.

Each server bridges the computer Ethernet adapter to the OpenVPN TAP adapter so that remote computers can use the server's LAN for Windows networking. For the bulk of the time, the system functions as intended.

I've done extensive testing and have observed the following:
1) The crashes occur whether or not the OpenVPN services are running.

2) The crashes occur only when the server is being written to by any program, e.g. an FTPS client, while the network bridge is installed. (Each server is concurrently running the Filezilla FTPS server.)

3) The crashes never occur unless the OpenVPN TAP is bridged to the computer's Ethernet adapter.

I've captured some screen shots from one of the servers while it was being written to by a Filezilla client while the OpenVPN server was installed but deactivated, i.e., none of the OpenVPN services were running. However, the Ethernet adapter was bridged to the TAP adapter.

About 2 TB of data was being moved from the client to the server via Filezilla with the client set to automatically retry upon a failure. The screen shots were captured after the data transfer was completed.

I also perform this same data transfer without the bridge and had no crashes. So it appears that there is some unfavorable interaction between OpenVPN TAP adapter and Windows.

Attachments (11)

Server3_Critical_Events_List.jpg (207.2 KB) - added by mpfrench 7 months ago.
Server3 Critical Events List
Server3_Event_41_Kernal-Power.jpg (63.3 KB) - added by mpfrench 7 months ago.
Server3 Event_41 Kernal-Power
Server3_Minidump1.jpg (202.0 KB) - added by mpfrench 7 months ago.
Server3 Minidump 1
Server3_Minidump2.jpg (202.1 KB) - added by mpfrench 7 months ago.
Server 3 Minidump 2
Server3_Minidump3.jpg (202.4 KB) - added by mpfrench 7 months ago.
Server 3 Minidump 3
Server3_Minidump4.jpg (200.9 KB) - added by mpfrench 7 months ago.
Server 3 Minidump 4
Server3_Minidump5.jpg (202.3 KB) - added by mpfrench 7 months ago.
Server 3 Minidump 5
Server3_Realtek_Ethernet_Driver.jpg (65.7 KB) - added by mpfrench 7 months ago.
Server 3 Realtek Ethernet Driver
Server3_Network_Connections.jpg (49.4 KB) - added by mpfrench 7 months ago.
Server 3 Network Connections
Server3_Network_Bridge_Properties.jpg (64.9 KB) - added by mpfrench 7 months ago.
Server 3 Network Bridge Properties
Server3_Configure_Network_Bridge_Porperties.jpg (63.0 KB) - added by mpfrench 7 months ago.
Server 3 Configure Network Bridge Properties

Download all attachments as: .zip

Change History (17)

Changed 7 months ago by mpfrench

Server3 Critical Events List

Changed 7 months ago by mpfrench

Server3 Event_41 Kernal-Power

Changed 7 months ago by mpfrench

Attachment: Server3_Minidump1.jpg added

Server3 Minidump 1

Changed 7 months ago by mpfrench

Attachment: Server3_Minidump2.jpg added

Server 3 Minidump 2

Changed 7 months ago by mpfrench

Attachment: Server3_Minidump3.jpg added

Server 3 Minidump 3

Changed 7 months ago by mpfrench

Attachment: Server3_Minidump4.jpg added

Server 3 Minidump 4

Changed 7 months ago by mpfrench

Attachment: Server3_Minidump5.jpg added

Server 3 Minidump 5

Changed 7 months ago by mpfrench

Server 3 Realtek Ethernet Driver

Changed 7 months ago by mpfrench

Server 3 Network Connections

Changed 7 months ago by mpfrench

Server 3 Network Bridge Properties

Changed 7 months ago by mpfrench

Server 3 Configure Network Bridge Properties

comment:1 Changed 7 months ago by tct

Having the 2 TB target is sort of useful. I can retest this on Win7 hardware sometime.

@mpfrench, would you be able to test this while the bridge exists between two real ethernet cards and no TAP adapter ?

comment:2 Changed 7 months ago by Gert Döring

So this is either a bug in Win7/Win10 bridging (= would be exhibited by lan-to-lan bridging as well) or in the TAP driver. No good idea how to tackle this, though, as we're all not really skilled windows driver developers.

The general recommendation is "do not do this", though - do not use TAP mode, do not use bridging. DNS exists, AD exists, and windows networking works great over routed links - no need for bridged netbios naming requests.

comment:3 Changed 7 months ago by stipa

Would it be possible to see the stack trace? You could attach to problematic machine with windbg in advance and then when crash occurs it should break into debugger.

comment:4 Changed 6 months ago by tct

I found time to test this on Win7 OpenVPN-Server Real hardware.

Copied more than 4GB of data over a Bridged VPN with no problems at all.
I had to pull the data from a Linux server (VPN Client) to the VPN server.
I would not call this test exhaustive but it is at least something ..

Real hardware: This server is Win7 Home Premium on a laptop with 3GB RAM and a Celery chip. It is so old that it has had to have a new power supply (because the old one got ripped out too many times), the screen does not work, so uses an external monitor, and six keys are missing from the keyboard.

And it still works !

BTW: Easy-TLS a great for inlining all your X509.

Last edited 6 months ago by tct (previous) (diff)

comment:5 in reply to:  description Changed 6 months ago by tct

Replying to mpfrench:

Each server is concurrently running the Filezilla FTPS server

Free or Pro ?

comment:6 Changed 6 months ago by Gert Döring

Milestone: release 2.5release 2.5.3
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