I prefer to run a reverse proxy in a DMZ VLAN instead of on the firewall itself. I tried it one time and had issues with a node showing offline but I didn’t try setting up a 3rd node - tried to make one mode count twice so maybe one issue I had. I’ve heard people have issues with clustering on Proxmox and I’ve heard some say it’s flawless. Of course you can create a cluster but you need 3 nodes (some set up a 3rd node on a Raspberry Pi for quorum). If I would virtualize OPNsense on Proxmox, I personally would not run it on the same Proxmox server where I ran all my other apps and services because I tinker enough on that system that I don’t want my network to go down cause something messed up. You can backup the configuration in OPNsense for restoring bare metal installations but there is still some work to do to get back up and running because you have to reinstall plugins, etc. I’ve always preferred bare metal for OPNsense since I have it on dedicated hardware but virtualization has tempted me because of how easy it is to backup the entire system.

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