Prerequisites

Now, let's review some of the prerequisites you need to take care of before setting up IPsec VPN tunnels in pfSense. When you are trying to establish IPsec tunnels between two networks, you must make sure that both locations are using non-overlapping LAN IP subnets. For example, if both sites are using 10.0.0.0/24 on the LAN segment, the IPsec site-to-site VPN will not work. This is not a limitation in pfSense; it's due to basic IP routing. If the pfSense server is not the default gateway on the LAN where it is installed, then some static routes must be added to the default gateway pointing the remote VPN subnet to the IP address on pfSense in the LAN subnet. You must have good communication with the administrator of the remote network so that you can coordinate the activities that are needed to set up the IPsec tunnel. There are a lot of settings that...