Azure + Ubuntu + OpenJDK 11 + Docker-compose = Unable to connect

[Lanttu42]

Hi everyone!

I had this wonderful idea that I could make Minecraft server to my friends kids, but this wasn't the easiest job and I failed!

If you have any ideas which I could try, please share - Here's my current setup and installation procedure:

I am running Ubuntu 18.4. on Azure environment and it is supported with OpenJDK 11 (sudo apt install default-jre).

• I made folder named "mine" under my useraccount
• I created docker-compose.yml which currently looks like this:

version: '3'
services:
  mc:
    image: itzg/minecraft-server:java11
    ports:
      - "25565:25565"
    volumes:
      - ./data:/data
    environment:
      EULA: "TRUE"
    restart: always

• Originally it didn't have the :java11 docker switch and I moved data under data folder, so I could keep my server settings file and also check if the issue lies on that file.
• I launched docker with docker-compose up -d
• Docker pulled necessary files, and populated data folder as expected
• I edited Azure Network security Group and allowed port 25565 ANY-ANY, All protocols
• I also added 25575 as I found it from server settings (rcon port)

I tried to launch Minecraft PE on my iPhone.

• Added server with IP -address
• It went under Other Server (as expected, I think?)
• It never got the PING and if I tried to connect, it says Unable to Connect

I tried also launch Minecraft Windows edition

• Added server with IP-address
• Unable to connect

iPhone version is updated to latest version.
Windows version is updated to latest version.
I don't have any VPN or outgoing firewalls.

I can succesfully run Valheim, Factorio and couple of older games without any issues.

[itzg]

If you're using iPhone and Windows edition client, then you're using the wrong server image. Use bedrock edition instead:

https://github.com/itzg/docker-minecraft-bedrock-server

[itzg]

I have never been quite sure about that second port, but I have only needed to expose 19132. Speaking of which, double check the network security context is UDP and not TCP for that port.

[Lanttu42]

Not quite sure did I understod your last note correctly, but I got it working!

I changed Azure NSG rule from Any Protocol to UDP Protocol and then I also added allow ICMP (which should not even work, because Azure servers wont accept ping even if you add that). Maybe it was that UDP protocol setting or ICMP allow setting that helped, but now I can connect to the server. :)

Thank you for the support!

[Lanttu42]

Atleast I got it working once. :D Now it just says Unable to Connect after I restarted the game. :D

[Lanttu42]

I have never been quite sure about that second port, but I have only needed to expose 19132. Speaking of which, double check the network security context is UDP and not TCP for that port.

Well, I think that this was the main issue. The second and random IPV4 (and 6) port seems to be a bug (https://bugs.mojang.com/projects/BDS/issues/BDS-10608?filter=allopenissues) and it doesn't seem to matter at all...

But this is annoying!
As I previously wrote, I tought that the game only worked once, because I got this "Unable to connect" when I restarted the game on iPhone and choosed my server from Servers list. I went totally haywire while I was debugging this - I even deleted my whole virtual machine and reinstalled it.

And got it working again - But only ONCE...

Then I noticed that "Friends" tab on the Minecraft PE game had changed from 0 to 1. I have no Friends, so something fishy must be happening there! I opened the Friends tab and there it is! My server as a Dedicate LAN game on Friends list! Just a stupid UX behaviour that is. But that is again Minecraft / Mojang issue. Not related to this project. :)

Thanks! Hopefully this chat helps someone.

[itzg]

Thanks for providing the follow up info.

Yes, even on a local network I have had to force-quit my iPhone client to get the server connectivity to come back.