10 OpenVPN™ Encryption
The Installation Wizard also installed a Windows Service for OpenVPN in the Services applet of
the Control Panel. The Startup Type is defined as "Manual", so it does not start without special
user interaction or required by a dedicated application.
When the openvpn.exe program is started by means of this service, it scans the "config"-subfolder
for configuration files of type ".ovpn". Each file causes OpenVPN to establish a connection, at least
it attempts to do so. If the NetCom Plus is not available at that moment, OpenVPN will try again
and again. When the NetCom Plus becomes available, the connection is established.
Figure 115: Start OpenVPN Service
Figure 116: Service Options
For the first test start the Service manually by click on the "Start" link. Windows displays the
progress. The connection of OpenVPN will be opened. Verify this by web browser or PING. When
a service is started, Windows offers the option to "Stop" or to "Restart" it. Stopping the OpenVPN
service will close all connections, Restarting will shortly drop and then re-establish them.
Figure 117: Startup Types
As each other service, also the OpenVPN ser-
vice has three different types for Startup. When
it is Disabled the service can’t be started at all.
Configured for Manual it requires explicit ac-
tion to run the software. If the service is con-
figured for Automatic start, the program is run
when all drivers are finally loaded, and a user
may log on to the system. But note, no user actually needs to log on to start the program. It is
started independent from Startup options configured for any user.
When the configuration file "client.ovpn" is in its final state, it may be convenient to set the
OpenVPN service to Automatic Startup Type. Even when the Virtual Serial Ports are only used
by a dedicated user when he is logged on, nobody needs to care about enabling the network link.
It will be simply available.
10.4 OpenVPN™ without Encryption
The implementation of OpenVPN™ in the NetCom Plus Serial Device Servers also offers to use
the VPN tunnel without encryption.
Why should one use a VPN tunnel for encryption, but
actually transmit plaintext data? This option provides for a very simple setup to communicate
through a complex network of Firewall implementations. As described in section Firewall Traversal
Configuration, there are many parameters to provide for passing a Firewall Router, especially when
this uses NAT for protection. If there is more than a single Router, this can be a lot of work. Now
with OpenVPN™ only one single TCP connection must pass through the Router.
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NetCom Plus User Manual
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Summary of Contents for NetCom Plus 111
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