IPV6 with the same IPV4 port using `SERVER_PORT_V6`

[brauliobo]

Hi,

I'm trying hard to use this docker with IPV6 but really can't... IPV4 is working normally when I delete the AAAA IPV6 record from the DNS. I tested with netcat for android and ports are open and visible with IPV6 through a 4G external connection.

This is the command I'm using:

export PORT=19132; docker run --name=mc$PORT --restart=always -d -it -e EULA=TRUE -e SERVER_PORT_V6=$PORT -e SERVER_NAME=$PORT -e ALLOW_CHEATS=true -e DIFFICULTY=easy -e MODE=survival -e VERSION=latest -e SEED=4515655456848273743 -p $PORT:19132/udp -v mc-bedrock-data-$PORT:/data itzg/minecraft-bedrock-server

and docker ps output:

➜  braulio  docker ps
CONTAINER ID   IMAGE                           COMMAND                  CREATED         STATUS                                     PORTS                                             NAMES
faf0e7b2c263   itzg/minecraft-bedrock-server   "/usr/local/bin/entr…"   4 minutes ago   Up Less than a second (health: starting)   0.0.0.0:19132->19132/udp, [::]:19132->19132/udp   mc19132

[brauliobo]

Tried with another port -p 19133:19133/udp and -e SERVER_PORT_V6=19133 and it worked! Can't it run on the same port? I see errors after pulling the latest image:

[2025-05-20 00:16:08:166 ERROR] Port [19132] may be in use by another process. Free up port and re-run program or adjust server.properties file to use alternate ports for server
[2025-05-20 00:16:08:166 ERROR] Port [19132] may be in use by another process. Free up port and re-run program or adjust server.properties file to use alternate ports for server

Also without SERVER_PORT_V6 IPV6 don't work. I think IPV6 should be enabled by default with the same port

[itzg]

It's binding IPv4 to port 19132 by default, so no, you can't also bind 19132 for IPv6 within the container. Make sure you're watching the logs to see what's going on. You didn't provide those, so it's hard to tell.