@matthewadams12 Why do you need the Fog Server to be offline?
Maybe there’s a solution where we can isolate just the part you want to isolate. i.e. if you are trying to remove internet access where images are stored you could setup a storage node and keep that offline after initial install. The storage node would also need packages and updates to fog, but you could capture them during updates on the main server and then sneakernet them to the storage node.
Storage nodes are just what I’m using as an example. If it’s not the images stored on the server you’re trying to isolate, then there could still be another solution. You could also firewall the server with your external firewall or the os firewall to only allow access to the fog github page for update downloads and then the repo sites that download the package updates?
Just thought I’d throw out some other possibilities.