Selfhosted @lemmy.world FarraigePlaisteach @lemmy.world 3 mo. ago

Is it possible to run a reverse proxy only on a specific service or port?

I’m happily serving a few websites and services publicly. Now I would like to host my Navidrome server, but keep the contents private on the web to stay out of trouble. I’m afraid that when I install a reverse proxy, it’ll take my other stuff ~~online~~ offline and causes me various headaches that I’m not really in the headspace for at the moment. Is there a safe way to go about doing this selectively?

34 comments

That's the standard behavior. Read the documentation for whatever reverse proxy you want to use.
- The standard is that everything gets captured by the proxy? I want to leave the HTTP and Gemini servers public. I also want those and SMB to remain accessible on the LAN.
  
  No, the standard is that it routes only what you configure.
I just don't put the ports on the proxy config.
- So those ports that I don’t put in the config remain publicly accessible? That would be perfect.
  
  The ports you don't put in are not publicly routed.
  
  I use NPM and only have 3 services routed outside my network.
I’m afraid that when I install a reverse proxy, it’ll take my other stuff online and causes me various headaches that I’m not really in the headspace for at the moment.

If you don’t configure your other services in the reverse proxy then you have nothing to worry about. I don’t know of any proxy that auto discovers services and routes to them by default. (Traefik does something like this with Docker services, but they need Docker labels and to be on the same Docker network as Traefik, and you’re the one configuring both of those things.)

Are you running this on your local network? If so, then unless you forward a port to your server on the port your reverse proxy is serving from, it’ll only be accessible from the local network. This means you can either keep it that way (and VPN in to access it) or test it by connecting directly to your server on that port and confirm that it’s working as expected before forwarding the port.
- Thank you so much. That clears up all my doubts. I’m running an ARM server ok the lan with port forwarding for HTTP (80) Gemini (1965) and SMB (not forwarded).
  
  I made a typo in my original question: I was afraid of taking the services offline, not online.
  
  I made a typo in my original question: I was afraid of taking the services offline, not online.
  
  Gotcha, that makes more sense.
  
  If you try to run the reverse proxy on the same server and port that an existing service is using (e.g., port 80), then you’ll run into issues. You could also run into conflicts with the ports the services themselves use. Likewise if you use the same outbound port from your router. But IME those issues will mostly stop the new services from starting - you’d have to stop the services or restart your machine for the new service to have a chance to grab the ports while they were unused. Otherwise I can’t think of any issues.
First of all, doesn't Navidrome have authentication? So, I don't see why exposing it to the public is a problem.

Second, some reverse proxies support basic auth. This way, you can password-protect some services and is useful if the service does not have its own authentication. Here as an example snippet for Caddy:

example.com { basic_auth { # Username "Bob", password "hiccup" Bob $2a$14$Zkx19XLiW6VYouLHR5NmfOFU0z2GTNmpkT/5qqR7hx4IjWJPDhjvG } reverse_proxy myservice:8000 }

You'll have to look up the docs for other reverse proxies.
- Thanks. You’re right about Navidrome supporting authentication. I’m using HTTP instead of HTTPS, though. I was advised to use a reverse proxy to avoid potential legal issues.
  
  What's your reason for using HTTP? That seems like a really bad idea this day in age, ESPECIALLY if that's something you're going to make available on the internet.
  
  How will a reverse proxy help?
  
  Things that a reverse proxy is often used for:
  
  making multiple services hosted on the same IP and port
  
  SSL termination so that the wider world speaks https and the proxy speaks http to the server. This means the server doesn't have to do its own key management
  
  load balancing services so multiple servers can serve the same request (technically a load balancer but I believe some reverse proxies do basic load balancing)
  
  adding authentication in front of services that don't have their own (note that some of the protections/utility is lost if you use http. Anyone who can see your traffic will also be able to authenticate. It's not zero protection though because random internet users probably can't see your traffic)
  
  probably something I'm forgetting
  
  Do any of these match what you're trying to accomplish? What do you hope to gain by adding a reverse proxy (or maybe some other software better suited to your need)?
  
  Edit: you say you want to keep this service 'private from the web'. What does that mean? Are you trying to have it so only clients you control can access your service? You say that you already have some services hosted publicly using port forwarding. What do you want to be different about this service? Assuming that you do need it to be secured/limited to a few known clients, you also say that these clients are too weak to run SSL. If that's the case, then you have two conflicting requirements. You can't simultaneously have a service that is secure (which generally means cryptographically) and also available to clients which cannot handle cryptography.
  
  Apologies if I've misunderstood your situation
A typical use case is to forward a single port to the proxy, then set the proxy to map different subdomains to different machines/ports on your internal network. Anything not explicitly mapped by the reverse proxy isn’t visible externally.
A reverse proxy is basically a landing place that acts as a middle man between the client and the server. Most people set it up so that all traffic on 80 or 443 go to the reverse proxy, and then the reverse proxy gets the correct website based on the host header of the request.

If you are currently serving multiple websites on your server, then that means you are serving each website on a different port.

So, just make sure that the reverse proxy is serving on a port that is not used by your other sites. It will only respond on it's own port, and it will only serve the site(s) that you have configured in the proxy.

You'll be fine!
- Thanks, that’s a great explanation. I’m looking forward to being able to SSH in without port forwarding.
  
  I would use a VPN to ssh
  
  I agree that you would want a VPN for that. Look into something like tailscale.
My method:

VPS with reverse proxy to my public facing services. This holds SSL certs, and communicates with home network through WireGuard link configured on my router.

Local computer with reverse proxy for all services. This also has SSL certs, and handles the same services as the VPS, so I can have local/LAN speeds. Additionally, it serves as a reverse proxy for all my private services, such as my router/switches/access point config pages, Jellyfin, etc.

No complaints, it mostly just works. I also have my router override DNS entries for my FQDN to resolve locally, so I use the same URL for accessing public services on my LAN.
- Thanks! Is the point of reverse-proxying your public-facing services to make them private?
  
  It's mostly so that I can have SSL handled by nginx (and not per-service), and also for ease of hosting multiple services accessible via subdomains. So every service is its own subdomain.
  
  Additionally, my internal network (as in, my physical LAN) does not have any port forwarding enabled --- everything is over WireGuard to my VPS.
How are you currently serving publicly?
- Linux running HTTP and Gemini servers. This is fine from home using port forwarding and afraid.org’s dynamic DNS.

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