[ELI5] What is a reverse proxy exactly and how do I use it to run several dockerized services on one machine?
So, I have some idea on what a reverse proxy does and will be using nginx (with the neat proxy manager UI) for my setup.
However, I'm not completely clear what exactly I want it to do and how I cn use it to run different services on one machine. I'm especially unclear on the ports configuration .... tutorials will say things like "change the listening port to xxx for that service and to port yyy for the other service"
How does this work, which ports can I use and how do I need to configure the respective services?
EDIT: thanks everybody, your replies did help me a lot! I have my basic setup now up and running using portainer + nginx + fail2ban.
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One big thing they’re used for is sort of multiplexing port 80/443. You have one daemon listening on them, and you can have multiple domains pointing at the same IP. The reverse proxy will figure out which backend service to forward requests too.
Proxies like Caddy and I think Traefik also automatically manage SSL certificates. In many cases you could have your application server handle SSL, but usually it’s a good idea to have dedicated software for this.
Could you have a look at my answer to the poster above - would multiplexing mean, that I configure my internal IP 0.0.0.0:XXXA for one service and 0.0.0.0:XXXB for another?
Yeah that’s exactly right! You have the proxy listen on 80/443 and use the subdomains to proxy to the respective other services that you have listen to other ports. Make sure those other ports are not open to the outside, though, as that would allow someone to bypass the proxy. In you example, you would change away from 0.0.0.0 to 127.0.0.1, which means the port is only open to the loop back interface, not the other ones. This happens accidentally especially when using docker for the app service. Also you should probably run some firewall to block all ports that you don’t wish to expose.
I’d really suggest you take a look at Caddy for the reverse proxy. It completely handles SSL certificate creation and renewal so you don’t have to do anything.
thank you, that clears things up a bit. Now it's to play around with it, until I get it up and running :)
For future reading this "multiplexing" is called SNI inspection/routing and it can only be used when TLS/SSL is in use.
You can already do that without a reverse proxy.
A reverse proxy allows you to have multiple services running on 0.0.0.0:XXXA
For example you might have two websites at a server on 192.168.0.123
Your server will be setup to show those websites at two different ports, say "192.168.0.123:123" and "192.168.0.123:321" - with foo.com on 123 and example.net at 321
Your reverse proxy will listen to requests on port 80 (where websites are usually served) and look at each request. If it's a request for the website at foo.com, it'll send it to port 123. If it's a request for example.net it will send it to port 321
But the client who is requesting the sites will only see port 80, at the same IP address for both sites.