Morgikan

My biggest concern is pivoting. Specific to Jellyfin, many users are using docker, but do not isolate the user so the daemon is operating as root. With that setup, an attacker could mount the host filesystem to the container and would own the host from that container.

Again, for the linux mention, the answer is pivoting. Many machines use Tailscale. If one of those machines were to be compromised using Tailscale’s default ACL, they would be able to move laterally through the network without issue. At that point, it would be possible to modify existing nodes (ex. subnet routers, exit nodes, etc) or even add additional rogue nodes.

The question of why people care is tricky. Why should you care if your networked printer is using out of date firmware? It likely isn’t storing personal information, right? It’s a prime target because it’s easy, poorly monitored, and opens another door. A lot of infosec is just keeping doors shut so other doors don’t get opened.

If the goal is doing this in a simple fashion, then use Tailscale funnels (https://tailscale.com/docs/features/tailscale-funnel). Funnels automate the process and act as a reverse proxy into specific servers within your tailnet.

The downside is there is no authentication to funnels, so whatever you’re running (Jellyfin in this case so that’s not an issue) needs it’s own authentication setup. You might consider running fail2ban on that machine and have it watch for login attempts, but otherwise that is the simplest setup I think you could do.

I had pfSense running on an old Core 2 Duo machine from around 2010 when I worked in MSP. You can run it on just about anything.

The only trouble I had was when I switched to gigabit+ service and had snort running. Snort is single-threaded and that CPU just could not keep up. Suricata would be a better choice given it’s natively multi-threaded, but the real limitation there was my setup and not pfSense.

Bob Saget would roll in his grave if he heard about your addiction.