Issue New Client Key
cd /etc/openvpn/easy-rsa/ source vars ./build-key client1
This creates the files 'client1.crt', and 'client1.key' in '/etc/openvpn/easy-rsa/keys/'.
These two files along with 'ca.crt' should be copied into a new directory in '/root/vpnkeys/'. You can then generate a tarball of the new directory for distribution to the client machine.
Reference: Official 12.04 OpenVPN Guide
Do not use NetworkManager-OpenVPN, it appears to mess with the routing in a way that I can't work out how to fix.
sudo apt-get install openvpn
Unpack your key bundle into /etc/openvpn/
Then copy the below file to /etc/openvpn/client.conf and edit the cert and key entries for the filenames from your key bundle: (can also use 184.108.40.206 for clients that may not have working dns)
client dev tun proto udp remote philcrump.co.uk 1194 resolv-retry infinite nobind persist-key persist-tun ca ca.crt # Put your filenames here: cert client.crt key client.key # ^^^^ ns-cert-type server cipher AES-128-CBC comp-lzo verb 3
Start the Client and you'll quickly be connected! Use the following command to stop the Client.
sudo service openvpn start ... sudo service openvpn stop