I found the infos below on internet,
and check this topic on the forum about the same argument,
http://www.ourdreambox.com/ubbthreads.php?ubb=showflat&Number=2414#Post2414Admin
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1. Get/Create/Download your .conf file
2. Telnet onto your Solo2
3. Type in "opkg install openvpn"
4. FTP to your Solo2 and navigate to the /etc/openvpn directory
* You can't see this directory by default, just enter it as a path
5. Copy your .conf file onto the Solo 2
6. Rename your .conf file to "client.conf"
7. Type in mkdir /dev/net
8. Type in mknod /dev/net/tun c 10 200
9. From Telnet, type in /etc/init.d/openvpn start
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Initially thought OpenVPN was not installed. From Menu/Setup/../Network/OpenVPN showed "Enabled" but "Not Running" and when I clicked green it did not change and nothing was displayed in the log file.
I logged in via ssh and uninstalled OpenVPN and then re-installed to see what was going on - no errors.
I executed "openvpn" from the command line and hey presto i got output back from openvpn.
So next step was to get the config files for your OpenVPN connection.
MY provider ( AirVPN ) have a nice web interface that create the config files for you.
I was supplied with
ca.crt
user.crt
user.key
and a number of .ovpn files which are the ..config files to configure openVPN connection.
i copied all files to /etc/openvpn
and then from the command line i executed
openvpn ./italy.ovpn
but during the openvpn connection process i was getting error
Tue Jan 15 08:25:57 2013 Note: Cannot open TUN/TAP dev /dev/net/tun: No such file or directory (errno=2)
After some research it was clear the device /dev/net/tun needed to be created - i guess the question is why this isn't installed when you install OpenVPN , there maybe a good reason for this.
i found the following statements and ran
mkdir /dev/net
mknod /dev/net/tun c 10 200
I then re-ran
openvpn ./italy.ovpn
and got connected.
i stopped everything.
i renamed italy.ovpn to client.conf*
and then then from the command line executed
/etc/init.d/openvpn start
*
... need to work out how to log some info to log file but apart from that it looks to be working ok for me.