You can find a similar documentation to install and configure almost everywhere. This guide is for a connection between my Icingaserver and my QNAP, which I wanted to monitor. I dont configure this VPN for browsing the web or anything.

apt-get install openvpn easy-rsa

Create your configuration

gunzip -c /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz > /etc/openvpn/server.conf

Edit the following in “/etc/openvpn/server.conf

#from
dh dh1024.pem
#to
dh dh2048.pem

Edit and uncomment

user nobody
group nogroup

cp -r /usr/share/easy-rsa/ /etc/openvpn
mkdir /etc/openvpn/easy-rsa/keys

Edit the default vars in ”/etc/openvpn/easy-rsa/vars“

export KEY_COUNTRY="YOUR COUNTRY eg. DE"
export KEY_PROVINCE="YOUR PROVINCE eg. BW"
export KEY_CITY="YOUR CITY eg. Karlsruhe"
export KEY_ORG="YOUR ORG eg. Lunetikk"
export KEY_EMAIL="YOUR MAILADDRESS"
export KEY_OU="YOUR OU eg. lunetikk"

export KEY_NAME="ANY IDENTIFIER eg. openvpn"

Execute the following and if asked say “y” and enter

openssl dhparam -out /etc/openvpn/dh2048.pem 2048

cd /etc/openvpn/easy-rsa
. ./vars
./clean-all
./build-ca

Build the cert, if asked say “y” and enter

./build-key-server openvpn

Copy your cert and keys

cp /etc/openvpn/easy-rsa/keys/{server.crt,server.key,ca.crt} /etc/openvpn

and start the service

service openvpn start

execute the following, if asked say “y” and enter

./build-key qnap

copy the client sampleconfig

cp /usr/share/doc/openvpn/examples/sample-config-files/client.conf /etc/openvpn/easy-rsa/keys/qnap.ovpn

edit ”/etc/openvpn/easy-rsa/keys/qnap.ovpn“ and change the following

remote YOUROPENVPNSERVER 1194

#use these on qnap, make sure they exist
user nobody
group everyone

#comment the 3 lines
#ca ca.crt
#cert client.crt
#key client.key

#at the end of the file, add your ca, client-cert and client-key
<ca>
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----
</ca>

<cert>
Certificate:
...
-----END CERTIFICATE-----
...
-----END CERTIFICATE-----
</cert>

<key>
-----BEGIN PRIVATE KEY-----
...
-----END PRIVATE KEY-----
</key>

Edit the file ”/etc/config/vpn.conf“ and add the following

[OPENVPN_CLIENT1]
Enable = TRUE
Status = 1
Index = 1
Gateway = 0
Allow Connect = 0
Reconnect = 1
Server Address = lunetikk.de
Profile File = OpenVPN4
VPN Proto Type = udp
VPN Port = 1194
Compress = 1
Re-direct gateway = 1
Encryption = 1
AccessCode = AAA
Time Stamp = 0

Start your client (parameter 1 is the index in your config)

/etc/init.d/vpn_openvpn_client.sh start 1 &

Check if your connection is up with ifconfig and ping your gateway (openvpn server)

# ifconfig
tun0      Link encap:UNSPEC  Hardware Adresse 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          inet Adresse:10.8.0.6  P-z-P:10.8.0.2  Maske:255.255.255.255

# ping 10.8.0.1
PING 10.8.0.1 (10.8.0.1) 56(84) bytes of data.
64 bytes from 10.8.0.1: icmp_seq=1 ttl=64 time=38.6 ms
64 bytes from 10.8.0.1: icmp_seq=2 ttl=64 time=37.9 ms