Left 4 Dead 2

The following repository contains the source files for building a Left 4 Dead 2 server.

Running

To run the container, issue the following example command:

docker run -d \
-p 27015:27015/udp \
-p 27015:27015/tcp \
-e L4D2_SERVER_HOSTNAME="DOCKER L4D2" \
ghcr.io/netwarlan/l4d2

SteamCMD Download/Install Issues

Starting 11/27/2024, Valve removed L4D2 from the Anonymous Dedicated Server distribution list. More info here: ValveSoftware/steam-for-linux#11522

For this to work going forward, a username and password will need to be provided.

You can pass this to docker environment variables:

STEAMCMD_USER="your-username"
STEAMCMD_PASSWORD="your-password"
STEAMCMD_AUTH_CODE="ABC123"

• The above can be passed via docker run, or part of your compose.yaml both methods allow setting environment variables and passing them into the container via .env
• If you have MFA enabled on the account, you may also need to manually "Approve" the login request

Environment Variables

We can make dynamic changes to our L4D2 containers by adjusting some of the environment variables passed to our image. Below are the ones currently supported and their (defaults):

Environment Variable	Default Value
L4D2_SERVER_PORT	27015
L4D2_SERVER_MAXPLAYERS	4
L4D2_SERVER_MAP	c1m1_hotel
L4D2_SERVER_HOSTNAME	L4D2 Server
L4D2_SVLAN	0
L4D2_SERVER_RCONPW	No password set
L4D2_SERVER_UPDATE_ON_START	true
L4D2_SERVER_VALIDATE_ON_START	false
L4D2_SERVER_ENABLE_REMOTE_CFG	false
L4D2_SERVER_REMOTE_CFG	No url set

Health Check

The container includes a built-in health check that monitors the game server process. Docker will automatically report the container as unhealthy if the game server stops running.

Check container health status:

docker inspect --format='{{.State.Health.Status}}' <container_name>

Troubleshooting

Server won't start

• Verify Steam credentials are correct
• Check if MFA approval is needed on your Steam account
• Review container logs: docker logs <container_name>

Slow startup

• First run downloads the full game (~15GB)
• Set L4D2_SERVER_UPDATE_ON_START=false to skip update checks after initial setup

Players can't connect

• Ensure ports 27015 TCP/UDP are forwarded correctly
• Check L4D2_SVLAN is set to 0 for internet play
• Verify firewall rules allow traffic on port 27015

License

This project is open source. See the repository for license details.