Preshared Key

Preshared Key Tunnel

--secret file [direction]: enables the use of 4 distinct keys otherwise 2 keys are used bidirectionally, one for HMAC and the other for encryption/decryption

Preshared Key/Secret

[]$ openvpn --genkey --secret static.key

Server

[]$ sudo openvpn --dev tun --ifconfig 10.0.0.1 10.0.0.2 --verb 3 --secret static.key 0

Client

[]$ sudo openvpn --remote server.example.com --dev tun --ifconfig 10.0.0.2 10.0.0.1 --verb 3 --secret static.key 1