Need a proxy

What exactly is the intention and setup here?

Like, are you self-hosting and looking for a way to "broadcast" the game, thus having a reverse proxy?

Or is it some other thing

Im self hosting but I want more than one server

Right now the intention is to hava a java + bedrock server and then a fabric server with a simple voice chat on it

I have a custom domain, and cloudflare ddns setup

so here's the thing. You can't have the same IP have 2 services running on the same port

so you can't have 2 servers running on 25565

Yes I understand, thats why a proxy could be used to route hostnames elsewhere

you can, however, use subdomains and SRV records

to just direct people to a different port

without needing a separate IP

Okay

so lets say I had like sub1.hostname.com

and sub2.hostname.com

if sub1 had the two ports it needed to point two

and sub2 has two different ones

I am not 100% sure on how SRV records work for geyser (where you have 2 ports) but in theory you can just set up 2 SRV records for the same A record

so your setup would be, as far as I know:

1) Change the port of one of the servers. Can't have both at 25565. Anything else works.
2) Create some records, namely an SRV record for the one not running on 25565. Minecraft by default tries to grab the IP you give it and use the default port, so I recommend not doing this on the geyser server as that's already pretty.
3) The SRV and A record could look something like the attached image. No worries about simple voicechat UDP, from experience it automatically sets itself up through TCP.

Yea

Can I use any port then

like 20000 and then 20001 for the first server

yes

above a certain port number that's reserved, and below 65000 something

need to set it up in the server.properties file too

would this be the correct way to set it up in my docker

nope

I run my servers through docker too, specifically pufferpanel. I have it opening as PORT:PORT

since changing the server-port in server.properties changes what port the server is listening to internally

so what I'd do is:

setup SRV for the server with voice chat, the geyser server would remain unchanged
open the ports you want for the vc server, and change the required settings in the properties file

what

...

Open the ports like 20000:20000

change the server.properties file of the mc server

create SRV records

Well no

isnt one internal in the docker

and external