Has anyone put together a solution that would provide IPMI access to my OPNsense firewall? I would like to be able to remotely do deployments of OPNsense, as long as I have LAN access. My current firewalls are in different buildings, that are connected by extended LANs.
What precisely are you trying to achieve?
Generally IPMI is an out of band management interface and most of the times the hosted OS is completely oblivious of it. Of course you can - on suitable hardware - access your IPMI LAN interface e.g. via SSH and connect to the serial console. Fujitsu offers that and of course OPNsense supports a serial console.
On Supermicro you commonly access the management interface with a web browser and get a VGA console and emulated USB keyboard via HTML5. OPNsense of course supports real VGA consoles.
So I am a bit a loss about your question.