Setup and Configuration
I tried to connect to a preconfigured virtual private network using the well known opensource software OpenVPN The installation and setup was done in a few minutes without any hassle. OpenVPN started by itself and was ready to connect to a network. Unfortunately it is a bit uncomfortable that the OpenVPN user interface is just accessible via the hidden taskbar icon.
Next I copied the given configuration and authentication files to the directoy
C:\Program Files\OpenVPN\config. The already running OpenVPN software recognized the newly added configuration file and enabled the “Connect” option.
Green connection but no network access
Connecting to the network was no problem. OpenVPN opened a connection log window, asked for the password and after a few seconds it announced the establishment of a a successful connection (windows notification) while automatically closing the connection log. Trying to open network resources or open a remote desktop connection results in several errors informing about a network problem. A simple ping command didn’t work either.
What was the problem? A connection was established. Everything looked fine and OpenVPN was telling the same. Or so it claims. When opening the connection log again it revealed multiple errors before establishing the connection. You can see a snipped in the following section:
Sun May 01 21:35:17 2016 ROUTE: route addition failed using CreateIpForwardEntry: Zugriff verweigert [status=5 if_index=14]
Sun May 01 21:35:17 2016 env_block: add PATH=C:\Windows\System32;C:\WINDOWS;C:\WINDOWS\System32\Wbem
Sun May 01 21:35:17 2016 ERROR: Windows route add command failed [adaptive]: returned error code 1
Sun May 01 21:35:17 2016 Initialization Sequence Completed
The solution is simple: OpenVPN started itself without requesting the necessary rights. After starting OpenVPN as Administrator the established connection worked as intended and the connection log was free from errors.