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Comment by 👻 mediocregopher

Re: "Reverse proxy for gemini vhosts"

In: s/Gemini

MITM all connections would _technically_ work, but I think at that point I would just not support it. That would essentially tie the backend to the proxy permanently, if the backend does anything with client certs, which wouldn't work for my case.

But luckily, after a bit of research, it seems it's possible to do it transparently. Since the TLS Client Hello message is sent plaintext at the start of the message, the server should be able to read just that, parse it, then forward it and the rest of the connection to the correct backend.

— https://jean.ribes.ovh/gemini-reverse-proxy-using-traefik/#navbar-end

If traefik can do it, I can do it.

👻 mediocregopher

Jul 18 · 5 months ago

19 Later Comments ↓

🤖 alexlehm · Jul 18 at 13:04:

I should say that a HTTPS reverse proxy would have the same problem if a client cert is used

🚀 skyjake · Jul 18 at 15:07:

Forwarding the connection does sound like a much better solution. It is beyond my level of expertise to evaluate whether it's a good idea, though... A reverse proxy that forwards TLS connections without modifying them seems like something that is pretty much protocol-agnostic?

👻 mediocregopher · Jul 18 at 15:48:

An HTTPS reverse proxy _would_ have the same problem if client certs were used, but fortunately (for http proxies) http client certs aren't really a thing.

And @skyjake yeah, it's a pretty protocol agnostic solution, which I guess is why traefik supports it despite almost certainly not deliberately supporting gemini. But it also precludes modifying HTTP headers on requests and such (like adding X-Forwarded-For), which I guess is why it's not more common in http proxies.

☕️ mozz · Jul 18 at 18:20:

Peaking the TLS SNI is the best way to go. The disadvantage is that if the client doesn't send the SNI, or if the SNI doesn't match the actual URL inside the gemini request, you're kind of screwed.

Also check out the PROXY protocol, which allows you to attach client information like the true IP address in the absence of having access to HTTP headers. I added support for this to jetforce although I'm not using it currently.

https://www.haproxy.org/download/1.8/doc/proxy-protocol.txt

🐙 norayr · Jul 21 at 12:24:

hello, i am trying to understand, if we have such a solution now?

based on what i read (and hopefully understand) i would prefer a server that forwards requests to different ports depending on domain name. but without doing mitm, i guess it can just forward everything back and forth?

🐙 norayr · Jul 21 at 12:25:

i as referred to this thread

— here

🤖 alexlehm · Jul 21 at 14:30:

@norayr the problem is that the proxy has to determine the hostname in the unencrypted part of the TLS protocol, which apparently works, but it unusual (the solution provided by relayd seems to work)

🐝 Addison · Jul 21 at 18:06:

— => Here's an NGINX config that uses SNI to do what you're asking. Cheers

🐙 norayr · Jul 21 at 20:39:

relayd? hmmm... did anyone already configure some capsules like that? can i find some example configurations somewhere?

🐙 norayr · Jul 21 at 20:45:

omg let me see!

👻 mediocregopher · Jul 22 at 06:16:

@norayr I'm not sure why relayd was brought up, but both the link about traefik that I posted earlier and the nginx config that Addison posted should be able to help

🤖 alexlehm · Jul 22 at 09:40:

@mediocregopher sorry that was mentioned somewhere else on the same topic, I confused the "channels"

👻 mediocregopher · Jul 24 at 17:32:

To follow up: I wasn't able to do transparent TLS proxying in rust+tokio due to the tokio_rustls crate not supporting it, ended up implementing it myself

— https://github.com/rustls/tokio-rustls/issues/6

🐙 norayr · Jul 26 at 06:42:

thank you for sharing. i looked at your code and issue comments and tried to understand it all. it looks like you have made a significant effort with a relatively new to you language, thank you for that too.

let's see how it continues. we need a reverse tls proxy tool.

i perhaps would use such a tool with more enjoyment if i knew it is written in go, since i percieve it as more simple and modernistic language (from what we have in the mainstream) just like i perceive gemini to be simple and modernistic. but rust is fine.

👻 mediocregopher · Jul 27 at 06:14:

As someone who primarily writes go, I totally agree with you :) but the project I'm working on is in rust, to help me expand my skillset a bit. I think the same strategy I've employed here could be done in go even easier, using a TeeReader

🐙 norayr · Jul 27 at 10:25:

oh so nice to hear it. well, let's see if they accept your changes, and if not then i am glad there is a go project you can contribute to.

🐙 norayr · Jul 27 at 21:59:

i am following the issue and i see you created another branch. waiting to get the solution, hopefully it'll compile for me, and configure several virtual hosts for gemini on my server.

then i would move everything possible to gemini, and proxy with kineto.

👻 mediocregopher · Aug 09 at 15:01:

Some final closure on this thread, thanks for all the input everyone!

— mediocregopher.com/posts/domani.gmi

🐙 norayr · Aug 10 at 21:33:

so what happened in issue #6 of tokio-rustls? how did it end? did they accept your changes?

what is the solution if i want to do the same, i. e. host several of my gemini domains on one machine?

Original Post

🌒 s/Gemini

Reverse proxy for gemini vhosts — Reverse proxy for gemini I'm looking into writing a reverse proxy server which supports Gemini. ideally I'd like it to work like an HTTP reverse proxy like nginx or caddy, where it directs requests to different backend servers depending on the hostname. The problem is... is this even really possible, given that client certs are a thing? How can the proxy serve the connection long enough to figure out a hostname, and still proxy it to the backend server with...

💬 mediocregopher · 22 comments · Jul 18 · 5 months ago