I just had to set up a simple site to site VPN between a site with a fixed IP (SITE-B) and a site with a dynamic IP (SITE-A). Both routers are running the ‘Community Edition’ of pfSense and are installed on PC Engines APU.1C4. I have followed the documentation at pfSense.org about how to configure a Site To Site VPN with OpenVPN to get the VPN up and running. Because some things aren’t documented there I will put up my own HowTo here. Please do yourself a favour and read the documentation at pfsense.org first because it explains things in more detail than I will do here.

This HowTo will guide you trough the setup of:

• An IPv4 ‘Site To Site VPN’ with OpenVPN on the pfSense platform (2.3.4 at time of writing) as seen in the schema above with the specific settings for the PC Engines APU hardware platform.
• The client will autoconnect to the server and (in the event of disconnection) reconnect automatically.
• The authentication between the client and the server will happen automatically via pre-shared key.

• pfsense.org – OpenVPN Site To Site
• The pfSense Book