Site-to-site deployments using IPsec

This deployment type is commonly used to connect remote networks: for example, a branch office to a head office. In the past, it was common to use private lines/WAN connections based on Multiprotocol Label Switching (MPLS) and frame relay, for example. Nowadays, with large offers from ISPs of high-speed WAN connections, it is cost-effective to use a site-to-site VPN solution rather than contracting a private line service.

An example of multiple site-to-site VPN tunnels connecting branch offices to a head office is shown in the following diagram:

Figure 8.1 – Site-to-site VPN topology example

As we can see in the preceding diagram, the communication between the company offices is made by using the internet but protected by a VPN tunnel.

On OPNsense, we can use IPSec or OpenVPN to create a site-to-site tunnel. Let's see what the options are while creating an IPsec tunnel using the webGUI.

Note

We won...