https://community.openvpn.net/openvpn/wiki/Openvpn23ManPage

https://openvpn.net/index.php/open-source/documentation/howto.html

https://community.openvpn.net/openvpn/wiki/Concepts-Addressing

https://community.openvpn.net/openvpn/wiki/ManagingWindowsTAPDrivers

https://community.openvpn.net/openvpn/wiki/RoutedLans

https://community.openvpn.net/openvpn/wiki/BridgingAndRouting

https://community.openvpn.net/openvpn/wiki/IgnoreRedirectGateway

If you want to run multiple OpenVPN instances on the same machine, each using a different configuration file, it is possible if you:

• Use a different port number for each instance (the UDP and TCP protocols use different port spaces so you can run one daemon listening on UDP-1194 and another on TCP-1194).
  • If you are using Windows, each OpenVPN configuration needs to have its own TAP-Win32 adapter. You can add additional adapters by going to Start Menu → All Programs → OpenVPN → Add a new TAP-Win32 virtual ethernet adapter.
    • If you are running multiple OpenVPN instances out of the same directory, make sure to edit directives which create output files so that multiple instances do not overwrite each other‘s output files. These directives include log, log-append, status, and ifconfig-pool-persist.