Configuring OpenVPN to Use Certificates

Open the configuration file in your favorite editor; of course you may also use Notepad:

All you have to do here is put # in front of the entry secret key.txt, which we adapted in our last chapter, and add the following five entries:

Entry in config file	Function
tls-server	OpenVPN will run in TLS-server mode (on a client you will have to add TLS-client)
dh keys/dh2048.pem	Use the Diffie-Hellman key stored in keys/dh2048.pem
ca keys/ca.crt	Use the CA certificate in keys/ca.crt
cert keys/VPN-Server.crt	Use my certificate in keys/VPN-Server.crt
key keys/VPN-Server.key	Use my key in keys/VPN-Server.key

In my test-bed network, where the local net is 10.10.10.0/24, and the tunnel network is 10.3.0.0/24, the simplest possible configuration file (C:\\ProgramFiles\OpenVPN\config\sample.ovpn on Windows) for an X509-enabled OpenVPN server is:

dev tap
ifconfig 10.3.0.1 255.255.255.0
tls-server
dh keys/dh2048.pem
ca keys/ca.crt
cert keys/VPN-Server...