Introduction

The OpenVPN's Windows TAP-drivers consists of four files for each platform (32/64-bit):

• <something>.cat: contains cryptographic signature for the actual drivers
• <something>.sys: contains the actual driver
• <something>.inf: contains driver metadata

If you need to run OpenVPN on Windows Vista/7 64-bit you have to use signed TAP drivers. Unless you sign them yourself, you need to extract drivers from an existing OpenVPN installer. See below for instructions.

OpenVPN installers come bundled with a command-line tool called <tap-windows-install-dir>\bin\devcon.exe for managing the TAP-driver. Two wrapper scripts, addtap.bat and deltapall.bat are also available in the same directory. For details on devcon.exe usage look at ​Microsoft's Devcon.exe documentation.

NOTES:

• OpenVPN 2.3_alpha1 and earlier devcon.exe was called tapinstall.exe.
• OpenVPN 2.3_rc2 installer does not install TAP utilities by default. This bug is fixed in later releases.

Installing and uninstalling TAP-drivers

Occasionally you may need play with different TAP-driver versions. In this case you can use devcon.exe from the Windows command-prompt. Below are some common commands:

To view information about an installed driver use

$ devcon.exe hwids <id>

To uninstall the TAP-driver use:

$ devcon.exe remove <id>

To install a new TAP-driver use

$ devcon.exe install <something.inf> <id>

To update a TAP-driver use

$ devcon.exe update <something.inf> <id>

Notes:

• <id> refers to the driver identifier which is tap0901 for OpenVPN 2.2+, but may be different in older/newer OpenVPN versions.
• <something.inf> is typically OemWin2k.inf.

By installing multiple times, you will create additional TAP-Windows adapter instances, which can be used for multiple concurrent VPN tunnels. It is also possible to install using Control Panel -> Add New Hardware, and it is possible to uninstall using Control Panel -> System -> Hardware -> Device Manager.

Extracting TAP-drivers from OpenVPN installers

Extracting TAP-drivers from an OpenVPN installer is relatively easy: you can use ​7-zip to open the installer executable. There are both 32-bit and 64-bit versions, but the latter are larger in size.

Renaming the TAP-driver

Look at this page for a script that can be used to rename TAP-drivers.