Running multiple servers with Host networking suddenly no longer working.

[Smokex365]

Have been running multiple server containers for awhile without issue with the host networking. Just in the last week or so it's only the first container will boot and then the rest fail with Error CommandLineMultiplayer.cpp:355: Hosting multiplayer game failed: Can't bind socket: Address already in use. I've made no changes to the vm's networking and no change to the compose prior to the issue appearing. The full closure error I'm getting is:

 10.481 Info UDPSocket.cpp:37: Opening socket at (IP ADDR:({0.0.0.0:34202}))
  10.481 Hosting game at IP ADDR:({0.0.0.0:34202})
  10.482 Info HttpSharedState.cpp:57: Downloading https://auth.factorio.com/generate-server-padlock-2?api_version=6
  10.558 Info AuthServerConnector.cpp:112: Obtained serverPadlock for serverHash (<hash>) from the auth server.
  10.558 Info ServerMultiplayerManager.cpp:808: updateTick(3640224) changing state from(CreatingGame) to(InGame)
  10.558 Info UDPSocket.cpp:49: Opening socket for broadcast
  10.558 Error InterruptibleStdioStream.cpp:55: Got EOF on stdin; closing
  10.558 Error CommandLineMultiplayer.cpp:355: Hosting multiplayer game failed: Can't bind socket: Address already in use
  10.558 Info GlobalContext.cpp:769: Deleting active scenario.
  10.649 Info ServerMultiplayerManager.cpp:119: Disconnecting multiplayer connection.
  10.649 Info ServerMultiplayerManager.cpp:808: updateTick(18446744073709551615) changing state from(InGame) to(DisconnectingScheduled)
  10.706 Info ServerMultiplayerManager.cpp:146: Quitting multiplayer connection.
  10.706 Info ServerMultiplayerManager.cpp:808: updateTick(18446744073709551615) changing state from(DisconnectingScheduled) to(Closed)
  10.706 Info ServerMultiplayerManager.cpp:166: Deleting active scenario (global = true).
  10.707 Info UDPSocket.cpp:237: Closing socket
  10.707 Info UDPSocket.cpp:267: Socket closed
  10.707 Info UDPSocket.cpp:237: Closing socket
  10.860 Info UDPSocket.cpp:237: Closing socket
  10.860 Info UDPSocket.cpp:267: Socket closed
  10.861 Goodbye

Changing the networking to bridge works fine and they all launch though don't show in the local server browser of course. My current compose is:

# https://github.com/factoriotools/factorio-docker
services:
  factorio-01:
    image: factoriotools/factorio:latest
    pull_policy: always
    container_name: factorio-01
    ports:
      - "34201:34201/udp"
      - "27015:27015/tcp"
    volumes:
      - /docker/config/factorio-01:/factorio
    environment:
      - PUID=1000
      - PGID=1000
      - DLC_SPACE_AGE=false
      - UPDATE_MODS_ON_START=true
      - PORT=34201
      #- BIND=192.168.0.32
      - RCON_PORT=27015
      - SAVE_NAME=factorio-01
      - USERNAME=user
      - TOKEN=token
    network_mode: host
    labels:
      com.centurylinklabs.watchtower.enable: true
      io.portainer.accesscontrol.users: admin
    restart: unless-stopped
  factorio-02:
    image: factoriotools/factorio:latest
    pull_policy: always
    container_name: factorio-02
    ports:
      - "34202:34202/udp"
      - "27016:27016/tcp"
    volumes:
      - /docker/config/factorio-02:/factorio
    environment:
      - PUID=1000
      - PGID=1000
      - DLC_SPACE_AGE=false
      - UPDATE_MODS_ON_START=true
      - PORT=34202
      #- BIND=192.168.0.32
      - RCON_PORT=27016
      - SAVE_NAME=factorio-02
      - USERNAME=user
      - TOKEN=token
    network_mode: host
    labels:
      com.centurylinklabs.watchtower.enable: true
      io.portainer.accesscontrol.users: admin
    restart: unless-stopped
  factorio-03:
    image: factoriotools/factorio:latest
    pull_policy: always
    container_name: factorio-03
    ports:
      - "34203:34203/udp"
      - "27017:27017/tcp"
    volumes:
      - /docker/config/factorio-03:/factorio
    environment:
      - PUID=1000
      - PGID=1000
      - DLC_SPACE_AGE=false
      - UPDATE_MODS_ON_START=true
      - PORT=34203
      #- BIND=192.168.0.32
      - RCON_PORT=27017
      - SAVE_NAME=factorio-03
      - USERNAME=user
      - TOKEN=token
    network_mode: host
    labels:
      com.centurylinklabs.watchtower.enable: true
      io.portainer.accesscontrol.users: admin
    restart: unless-stopped

I've run out of things to try (binding the interface, changing ports, etc.) and can't figure out why it's suddenly failing after being fine for months.

[fank]

Root Cause

After investigating this issue, I've identified the problem: multiple Factorio servers in host networking mode are trying to bind to the same broadcast socket (port 34196) used for LAN discovery.

Why This Started Happening Recently

When using network_mode: host, all containers share the same network namespace. Factorio servers use port 34196 for LAN game broadcasts to enable local server discovery. The error sequence shows:

1. ✅ First container starts → binds to game port (34201) → binds to broadcast socket (34196) → Success
2. ❌ Second container starts → binds to game port (34202) → tries to bind to broadcast socket (34196) → Fails: Address already in use

The Error InterruptibleStdioStream.cpp:55: Got EOF on stdin message is a red herring - it's normal for containers and not the cause of the failure.

This likely started happening due to stricter socket binding behavior in recent Factorio 2.0.x versions.

---

Solution: Disable LAN Broadcasting

Since you're running on host networking, you don't need LAN broadcast discovery (it only works on the local subnet anyway). The fix is to set the server visibility to disable LAN broadcasting.

Option 1: Use public Visibility (Recommended)

Edit each server's server-settings.json file and change the visibility setting:

{
  "name": "Your Server Name",
  "description": "Your Description",
  "visibility": {
    "public": true,
    "lan": false
  },
  ...
}

This will:

• ✅ Publish to Factorio's official matching server (players can find it in the Browse Public Games list)
• ✅ Prevent LAN broadcast socket conflicts
• ✅ Allow direct connections via IP

Option 2: Use hidden Visibility

If you want a completely private server (only direct IP connections):

{
  "name": "Your Server Name",
  "description": "Your Description",
  "visibility": {
    "public": false,
    "lan": false
  },
  ...
}

---

Implementation Steps

For each of your three servers:

1. Edit the server-settings.json file in each config directory:

   • /docker/config/factorio-01/config/server-settings.json
   • /docker/config/factorio-02/config/server-settings.json
   • /docker/config/factorio-03/config/server-settings.json

2. Set "lan": false in the visibility section (and optionally "public": true)

3. Restart your containers:

   docker-compose restart

---

Alternative: Continue Using Bridge Mode

If you prefer to keep LAN discovery enabled, you can continue using bridge networking mode. The only downside is that servers won't appear in the LAN browser, but they'll still be accessible via:

• Direct IP connection
• Public server browser (if visibility.public = true)

---

Let me know if this resolves your issue!