USG Behind pfSense

Long story short, I have two sites both with Unifi USGs running a site to site VPN connection. One of these sites will be getting a pfSense box to replace (or at least mostly replace) the USG.

I need to be able to keep this site to site connection going while the USG is behind pfSense. I have seen some other posts similar, but in my case, I do not need to use the USG for anything else. Its only purpose will be to establish the site to site VPN.

From what I’ve found, (correct me if I’m wrong) there is no way to accomplish a site to site VPN between pfSense and a USG. At least not one that is supported.

Obviously this is not ideal, and there are plans to uprade the other site to pfsense in the future, but unfortunately that is not possible right now.

Is the site to site vpn using IPSec protocol ?

Is so, you should be able to setup PFsense to be endpoint for the site to site vpn. IPSec VPN is a industry standard and you should be able to configure this between different firewall endpoints

IPSec Site-to-Site VPN between Unifi and pfSense | Linux System Administration | Ubuntu, Redhat & Cybersecurity (