Quelltext der Seite Activate OpenVPN Client on a Synology with DSM 4.0 with Certificates

Synology DSM 4.0 upwards brings along an OpenVPN client. It supports authentication by login credentials. However when you operate with certificates, things come a little complicated. Notably complicated if you want to work with a non user based passwordless authentication which works with key/certifcicate files. 

I found this solution:

* Create a dummy client profile. Pick an arbitrary user and an arbitrary password. Upload your ca.crt
* Then activate SSH on the Synology
* Then ssh into it as root (with the admin password)
* cd int the following directory:
 /usr/syno/etc/synovpnclient/openvpn
* create a directory to hold your keys
 /usr/syno/etc/synovpnclient/openvpn/keys
* store the client's key and certificate (crt and key file) which you previously created by your certificate authority
* edit the file named "client_xxxxxxxxx" to look like this:
 client
 dev tun
 remote (your OpenVPN server) (port)
 proto tcp-client
 tls-client
 remote-cert-tls server
 ca (your previously uploaded ca.crt - Watch out, is has a different file name! ca_oxxxxxxxxxxx.crt)
 cert keys/your_client's.crt
 key keys/your_client's.key
 script-security 2
 #reneg-sec 0
 #plugin /lib/openvpn/openvpn-down-root.so /etc/ppp/ip-down
 comp-lzo
 cipher (the one you are using on your OpenVPN server)
 tls-cipher (the one you are using on your OpenVPN server)
: This is just a sample, and you must make sure to consider the server settings.
* Then go to the DSM's web configuration gui and click on "connect"