Selfhosted

How about creating your own LAN within the untrusted network?

Something like an inexpensive OpenWRT router would do fine. Connect all your devices and the server to the router. They are now on a trusted network. Set up Wireguard on the OpenWRT router to connect to Proton so that your outbound traffic from all your devices is secured.

A lot of people have suggested Tailscale and it's basically the perfect solution to all your requirements.

You keep saying you need ProtonVPN which means you can't use Tailscale, but Tailscale actually supports setting up an exit node which is what you need. Put Protonvpn on the Raspberry Pi, then set it up as an exit node for your tailnet. There's a lot of people talking about how they did this online. It looks like they even have native support for bypassing the manual setup if you use Mullvad.

As long as every client has the ability to use Tailscale (I.e. no weird TVs or anything) this seems like it checks all your boxes. And since everything is E2EE from Tailscale, TLS is redundant and you can just use HTTP.

Hi again.

How about the following idea:

Set up ProtonVPN on the raspberry pi.

On all other devices (or at least those you want to use Jellyfin on), switch from using Proton to using Wireguard. Unlike your phone, the raspberry pi has no trouble running multiple VPNs. I think the ProtonVPN limitations in regard to not allowing split tunneling don't apply here, since all outgoing traffic will still go via Proton.

Essentially, the Pi would function as a proxy for all of your traffic, "and also" host Jellyfin. You would still connect to http://192.168.20.10:8096/ (or whatever) on your devices, but that address would only resolve to anything when you are connected to the pi via Wireguard. No HTTPs, but "HTTP over Wireguard", if you will.

Nots that this requires you trusting the pi to the same degree that you trust your phone.

For your static devices (PC, TV) this should solve the problem. Devices which you take with you, like your phone, unfortunately will loose internet connectivity when you leave your home until you switch off Wireguard, and switch on Proton, and not be able to connect to Jellyfin when you return home, until you switch them back.

Essentially, you would have a "home" VPN and a "on the go" VPN, though you never need to connect to both. There might be ways to automate this based on WiFi SSID on Android, but I have not looked into it.

The Pros:

• this should meet all your requirements. No additional expenses, no domain, no dynDNS; no selfsigned certificate or custom CA; traffic is never unencrypted; works on all common devices.
• Wireguard is sufficiently lightweight to not bog down the pi, normally
• this is actually well within the intended use-cases for Wireguard, so no "black magic" required in configuring it
• if you ever do decide to get a domain, you can configure everything to always be connected to your pi via Wireguard, even on the go! Not required though.

The Cons:

• when you are new to selfhosting, Wireguard is a bit daunting to set up. It is not the easiest to debug (don't worry, it's easy to tell IF it is working, but not always WHY it isn't working). Some manual route handling is probably also required on the pi. It should definitely be doable though, but might turn this Jellyfin thing from a weekend project to a 2 week project...
• I have no experience with how well the pi runs Jellyfin. If the answer is "barely", then adding multiple concurrent Wireguard sessions might be a bad experience. Though in this case, you could only switch Proton to Wireguard whenever you want to watch Jellyfin.
• the manual switching might be annoying, but that is the price to pay here, so to speak

Edit: someone else already mentioned setting up your own trusted network with a second router. IMO that is the better, more hassle-free option IF you are willing to shell out the money. My suggestion is the "free" version of that, essentially 😄

ProtonVPN in its free tier does not allow LAN connections

This is the limiting factor. In order to get around this, you'll have to put your Jellyfin server on the Internet. Hopefully you can enable port forwarding. If not, you have painted yourself into a corner.

If you cannot use self-signed or internal CA certs, you will also need a domain name, and something like Let's Encrypt to issue certs for that domain.

I read the old thread and now this one.

As I understand it, you want to create connection between clients on your lan, but you don't trust your lan, so it's like having a raspberry pi server and some client both on the coffee shop network and you want them to communicate securely?

Tailscale is what you want. Easy setup, free, and allows exactly this to happen.

I previously proffered some information in the first thread.

But there's something I wish to clarify about self-signed certificates, for the benefit of everyone. Irrespective of whichever certificate store that an app uses -- either its own or the one maintained by the OS -- the CA Browser Forum, which maintains the standards for public certificates, prohibits issuance of TLS certificates for reserved IPv4 or IPv6 addresses. See Section 4.2.2.

This is because those addresses will resolve to different machines on different networks. Whereas a certificate for a global-scope IP address is fine because it should resolve to the same destination. If certificate authorities won't issue certs for private IP addresses, there's a good chance that apps won't tolerate such certs either. Nor should they, for precisely the reason given above.

A proper self-signed cert -- either for a domain name or a global-scope IP address -- does not create any MITM issues as long as the certificate was manually confirmed the first time and added to the trust store, either in-app or in the OS. Thereafter, only a bona fide MITM attack would raise an alarm, the same as if a MITM attacker tries to impersonate any other domain name. SSH is the most similar, where trust-on-first-connection is the norm, not the outlier.

There are safe ways to use self-signed certificate. People should not discard that option so wontonly.

To be totally honest I didn’t read your entire post, but just from your intro I think we are in similar situations. ISP router, low costs, using only the hardware you have around. I’ve solved a lot of stuff with Tailscale. None of my services are public facing and instead I connect to them over Tailscale (could be replaced with wireguard).

The wall I’m hitting you or maybe others could help with, is accessing my services from sub domains of a single Tailscale address rather than having to type port numbers for everything. I know this involves a reverse proxy and DNS (I use PiHole for that), but I’m stuck trying to configure the two in a way that actually works. Once I finally ditch iOS for good I’ll probably just sync a hosts file between all my devices using Syncthing to help streamline the DNS situation.

One thing that I haven't seen anyone mention yet, in this post or the last one, how to you plan on aquiring videos for your server? If you plan on torrenting, you just have to pay for a vpn, Proton doesn't allow you to make p2p connections like that on a free account

Here's an idea: on your android device use something like Insular to create a work profile, that way you get its own VPN slot, add your selfhosted-related apps there along with Tailscale. You can keep ProtonVPN on for your other apps, while using TS for your "LAN away from home" stuff. Since Tailscale already encrypts all traffic, you don't have to worry about HTTPS, certs, et al.

Wow, there isn’t a single solution in here with the obvious answer?

You’ll need a domain name. It doesn’t need to be paid - you can use DuckDNS. Note that whoever hosts your DNS needs to support dynamic DNS. I use Cloudflare for this for free (not their other services) even though I bought my domains from Namecheap.

Then, you can either set up Let’s Encrypt on device and have it generate certs in a location Jellyfin knows about (not sure what this entails exactly, as I don’t use this approach) or you can do what I do:

1. Set up a reverse proxy - I use Traefik but there are a few other solid options - and configure it to use Let’s Encrypt and your domain name.
2. Your reverse proxy should have ports 443 and 80 exposed, but should upgrade http requests to https.
3. Add Jellyfin as a service and route in your reverse proxy’s config.

On your router, forward port 443 to the outbound secure port from your PI (which for simplicity’s sake should also be port 443). You likely also need to forward port 80 in order to verify Let’s Encrypt.

If you want to use Jellyfin while on your network and your router doesn’t support NAT loopback requests, then you can use the server’s IP address and expose Jellyfin’s HTTP ports (e.g., 8080) - just make sure to not forward those ports from the router. You’ll have local unencrypted transfers if you do this, though.

Make sure you have secure passwords in Jellyfin. Note that you are vulnerable to a Jellyfin or Traefik vulnerability if one is found, so make sure to keep your software updated.

If you use Docker, I can share some config info with you on how to set this all up with Traefik, Jellyfin, and a dynamic dns services all up with docker-compose services.

and Android devices only have one VPN slot enabled, I cannot use something such as Tailscale for encryption.

I solved a similar situation with a tailscale subnet router . a tailscale subnet router is a tailscale node that exposes the non-tailscale network to the tailscale network. This way I am able to access one of my routers (and its PBX) from all tailscale nodes. The android phone has only tailscale as a VPN. If i pay for mulvad I can have the rest of the traffic go over a mullvad node.

doesn't really help you here though, unless you install protonVPN on the pi and add that as a tailscale exit node.

OP, I have been facing the same situation as you in this community recently. This was not the case when I first joined Lemmy but the behaviour around these parts has started to resemble Reddit more and more. But we'll leave it at that.

I think I have a solution for you if you're willing to spend $2-$3 a month - set up a VPS and run a Wireguard server on it. Run clients on your devices and the raspberry pi and connect to it.

As for your LAN: from the discussion you linked, it seems that Jellyfin will use the CAs present in the OS trust store. That's not very hard to do on Linux but I guess if you have to do it on Android you'd have some more trouble. In either case, using a reverse-proxy (I like HAProxy but I use it at work and it might be more enterprise than you need, for beginners Caddy is usually easier) will fix the trouble you're having with your own CA and self-signed certs.

I am interested in the attack vector you mentioned; could you elaborate on the MITM attack?

Unfortunately, if you don't have control over your network, you cannot force a DNS server for your devices unless you can set it yourself for every individual client. If I assume that you can do that, then:

1. Set up DNS server on Pi
2. Set up CA on Pi
3. Create root CRT, CSR and server certs from it (bare-minimim setup)
4. Copy over this stuff to Jellyfin image/VM, and copy root cert to clients trust store.
5. Run reverse proxy in front of Jellyfin and configure the correct IP address of the reverse proxy with an A record in your DNS server.
6. Configure reverse-proxy with server/application cert.
7. Use RethinkDNS on Android to pass everything through the wireguard server hosted on the VPS, and set private DNS to the DNS server hosted on the Pi.

I think that should do it. This turned out more complicated than I imagined (it's more of a brain dump at this point), feel free to ask if it is overwhelming.

Again, Tailscale.

I remember you were worried about your ISP messing things up for you, hence the VPN. I would recommend creating a "Virtual Machine" that does all of your downloading to whatever hard drive you're using. That VM can have proton installed. Then, on your regular computer (not within the VM), you can host Jellyfin with no VPN involved, making it accessible at 192.168.0.xx.

I think this hits your goals without needing to expose Jellyfin to the Internet. Plus it has minimal technical complexity. Your downloading traffic will be VPN protected, but Jellyfin will still be accessible to your local network.
edit: You can set up a password for Jellyfin, protecting it from your internal threats.

edit2: You can use letsencrypt to create a certificate that picky clients will accept. Buy a domain, any domain, and configure the "A record" to point to 192.168.0.xx (your Jellyfin IP). Then tell your client to go to whatever domain you get, like "luigiliterallydidnothingwrongplzfree.com", then the client will have to use the internet to ask DNS what the IP address is, but after that, it will just use your local network.

edit3: Since you just have the raspberry PI, instead of using a Virtual Machine, you could have 2 separate SD cards. One only has the downloader and VPN installed, the other only has Jellyfin installed (no VPN). Then swap as needed.