Velocity not recognizing docker container name as valid IP.

[SpookyKipper]

I got error that Velocity is not accepting docker container name as IP:

[04:59:32 ERROR]: Unable to read/load/save your velocity.toml. The server will shut down.
java.lang.IllegalStateException: Invalid hostname/IP nameless_mc_1:25565
	at com.velocitypowered.proxy.util.AddressUtil.parseAddress(AddressUtil.java:44) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at com.velocitypowered.proxy.config.VelocityConfiguration.validate(VelocityConfiguration.java:160) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at com.velocitypowered.proxy.VelocityServer.doStartupConfigLoad(VelocityServer.java:310) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at com.velocitypowered.proxy.VelocityServer.start(VelocityServer.java:214) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at com.velocitypowered.proxy.Velocity.main(Velocity.java:64) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]

If you need my configurations, it's below. The reason i use Custom is that the jar download will fail if i use TYPE=VELOCITY then specific the build number and version etc.

velocity.toml:

[servers]
# Configure your servers here. Each key represents the server's name, and the value
# represents the IP address of the server to connect to.
Main = "nameless_mc_1:25565"
#factions = "127.0.0.1:30067"
#minigames = "127.0.0.1:30068"

# In what order we should try servers when a player logs in or is kicked from a server.
try = [
  "Main"
]

docker-compose.yml:

version: "3"

services:
  mc:
    image: itzg/minecraft-server
    ports:
      - 25566:25565
    environment:
      UID: 1002
      GID: 1002
      EULA: "TRUE"
      TYPE: "PAPER"
      PAPERBUILD: 379
      VERSION: 1.18.2
      ONLINE_MODE: "FALSE"
      INIT_MEMORY: "4G"
      MAX_MEMORY: "10G"
      ENABLE_COMMAND_BLOCK: "TRUE"
      GAMEMODE: "SURVIVAL"
      LEVEL-NAME: "SurvivalWorld"
      SPAWN-MONSTERS: "TRUE"
    tty: true
    stdin_open: true
    restart: unless-stopped
    volumes:
      # attach a directory relative to the directory containing this compose file
      - ./mc-data:/data

  db:
    image: mariadb
    volumes:
      - "./db:/var/lib/mysql"
    user: '1002' # change this
    environment:
      MYSQL_ROOT_PASSWORD: xxx
      MYSQL_USER: xxx
      MYSQL_PASSWORD: xxx
      MYSQL_DATABASE: xxx
    restart: unless-stopped
    networks:
      - net_kipper_ml
      
  velocity-proxy:
    image: itzg/bungeecord
    user: "1002:1002"
    stdin_open: true # docker run -i
    tty: true        # docker run -t
    environment:
      UID: 1002
      GID: 1002
      REPLACE_ENV_VARIABLES: "true"
      TYPE: "CUSTOM"
      INIT_MEMORY: "1G"
      MAX_MEMORY: "2G"
      BUNGEE_JAR_URL: "https://api.papermc.io/v2/projects/velocity/versions/3.1.2-SNAPSHOT/builds/150/downloads/velocity-3.1.2-SNAPSHOT-150.jar"
      #VELOCITY_VERSION: "latest"
  #    VELOCITY_BUILD_ID: 150
      DEBUG_GET: "TRUE"
    ports:
      - "25565:25577"
    volumes:
    #  - ./config.yml:/config/config.yml
      - ./proxy-velocity:/server
    restart: unless-stopped
    depends_on:
        - db
        - mc
    networks:
      - net_kipper_ml
  
networks:
  net_kipper_ml:
    external: true
    
volumes:
  proxy-velocity: 

[itzg]

Your velocity config is wrong. The service hostname is just "mc".

[SpookyKipper]

but it throws this error now https://imgur.com/a/jVlEPzb

[01:36:01 ERROR]: [connected player] SpookyKipper (/myip:55210): unable to connect to server Main
io.netty.channel.ConnectTimeoutException: connection timed out: mc/142.250.72.147:25565
	at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe$2.run(AbstractEpollChannel.java:613) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:170) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:394) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:995) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[velocity-3.1.2-SNAPSHOT-150.jar:3.1.2-SNAPSHOT (git-da52d093-b150)]
	at java.lang.Thread.run(Thread.java:833) [?:?]
[01:36:01 INFO]: [connected player] SpookyKipper (/myip:55210) has disconnected: Unable to connect you to Main. Please try again later.

[itzg]

I didn't notice before that you were using an externally configured network. The mc service needs to be on the same network as the proxy for the Docker name resolution to work.

[SpookyKipper]

So it means i have to put mc in the same network too.

[SpookyKipper]

It works, thanks.