check_openvpn is installed on the monitoring server and can be used to check if the udp port of a given OpenVPN server is reachable. If the udp port can be reached and gives a response, the script emitts the state "OK" and prints out the response in hex.
The script also supports checking of tcp ports, although in that case no response is gathered and thus only the state itself is emitted.
The development of the script was supported by cedativ GmbH